Before I started "arting", I was a fanfic reader/reviewer, and I'm pretty active in the "creative" side of fandoms, making friends with fanfic writers and fanartists.

When I started writing a fanfic for myself, I also posted my own drawings about the characters in that fanfic on deviantArt. A fellow writer who liked my fic (and therefore saw my drawings) then approached me and asked if I take commissions. This was sometime in the middle of 2010.

At that time I pretty much had nothing to do in my free time, it seemed like easy money, so I said "why not?" and drew this for her:



I didn't ask for much (about 10 USD, as I recall), since it was my first job and I didn't even own a digital tablet so my art was done through ink-on-paper and "filled" digitally using the mouse, which meant it was kind of crappy, but $10 USD was still something.

About a few days after the completed artwork was handed in to my client's inbox, I had some savings that I didn't know what to do with, so on a (very spendthrift) whim, I got myself a small Wacom tablet and Photoshop.

Anyway, that first client was pleased with my work, and when another writer friend of her saw that drawing, she asked where did she get it, and that client referred her to me. That lady become my second client, which I also charged cheaply. She liked it so much that she gave me a $100 USD "bonus" for the work.

No joke.

That first and second clients eventually became my "constant" clients, and if they wanted art for their writing, I provide it to them with a certain fee

Anyway, both of them started promoting me, mostly by word of mouth, and at the same time I was posting my drawings in fangroups based in deviantArt and Dreamwidth and Livejournal. That got me noticed a little bit, but not much, since I didn't post much art beyond what I had been commissioned to do at that time.

Then sometime during September 2010,  major fangroup on deviantArt was hosting a fanart competition, and for kicks, I joined in the comp, and digitally painted this:



Ended up in the top five out of about 70+ entries, I think. The art got me noticed a LOT, especially by the fangirls (and some boys who likes this sort of thing)

Around that same time, I also, err, ended up getting involved in a case of so-called art thievery on dA, which resulted in a major fight between in the same fangroup that hosted this competition. I'd been reading up on US copyright laws, and I was giving my two cents on what I know, and had been acting as a sort of mediator, because I was a "newbie" in that group and thus had no, as quote by someone, "political affiliations" (whatever the hell that meant) to any of the fighting parties involved.

THAT got me noticed much more than the art did, although I wish that situation didn't show up to begin with, and I ended up getting a moderator position in that group, as well as making friends with the "founders" (i.e. leaders) of several other major fangroups.

So, as I was gaining notoriety, another fic writer noticed my work, and she approached me with an idea to provide black and white illustrations for her fic chapters.

This was something of a long-term project, since she was in the middle of writing aforementioned fic. The way it worked, she has a posting schedule, and would upload a chapter every Wednesday and Saturday, which changed to every Monday and Friday, since she found that easier once she ended up writing another fanfic at the same time.

We had discussions over which chapter would benefit from artwork, and which is best left as plain text, but I was basically churning out two grayscale-shaded lineart drawings per week, from sometime late November last year all the way to the end of June this year, with two major breaks (Christmas for the writer, Chinese New Year and a month of ill health for me) in between. Sometime during this I also put out a "price list" for anyone interested in commissioning work from me.

There were a total of 36 drawings done for this project, each drawing priced at $12 USD. I was also doing other "standalone" commissions for other clients during this time period, so that wasn't the only money I was earning.

By the time it was May 2011, I'd already recovered the cost of the Wacom tablet I bought, as well as most of the price of the Dell Studio XPS PC I bought strictly for art/game purposes.

1) Promote yourself
Kind of important. Don't go bragging about what you can't do, obviously. But get your art out in the open for people to "see". The more eyes start seeing, the more mouths start talking, the more "interested" eyes start LOOKING, and the more hands start offering cash. The Internet is a powerful tool for exposure (although it DOES mean people can steal your art, but good art will naturally bring fans, and fans can become friends/allies to stop thievery), so get an art account, and start posting your stuff online.
2) Stay friendly and social
Also known as "networking". VERY important. No one likes a turd, and if you aren't being active in the community, NO ONE is going to know if you're a turd or not, or even know who you are, for that matter. Especially on the Internet, where everyone is anonymous by default. Join some groups, be friendly, make some friends, don't provoke enemies (and don't let enemies provoke you). Generally, be "nice", but DO be politely firm if you feel that you are being unfairly treated, which CAN happen even if you are doing things with the best intentions. Flame wars are the worst things to end up in, especially if you're in the range of fire. EVERYONE is going to get hurt.
3) Be honest, be real
To both yourself, and your clients. Do you know what's your level of "skill"? Don't charge prices like someone with twice your skill level, but don't under-charge yourself either. Client being something of a donkey to you? Don't let yourself be ridden over. No time for the job? Don't accept it if you can't do it, or if you're on a job and end up having to delay for some reason, TELL YOUR CLIENTS WHY, AND TELL THEM EARLY.

One thing I'd learned from a sales job I had for about two years is that the LAST thing you want to do is to break a promise you've made to your customer, and do your best to NOT mislead them, even accidentally. Otherwise you're going to get a very angry/disappointed customer on your hands, and a bad mouth is going to hurt your reputation badly.
4) Set standards.
For both pricing and subject matter. Pricing, you can find out how to charge from doing a little "look-see" or "surveying" on other artists' commission journals/adverts, and know where do you fall on that range. Subject matter... well, what are you good at? What are your specialities? What are you not-so-good at doing, and what do you absolutely NOT do? I'm a bit relaxed when it comes to subject matter, since I don't mind depicting violence and/or sexual situations, but I DO draw the line at things like bestiality, hardcore "furries", or things involving bad things happening to little children unless it's MEANT to be horrifying and not "fap material". If you're upfront about what you can/can't/won't/want-to do, clients know what to expect, and won't be TOO unrealistic.
5) Learn as you work.
Pretty obvious. Always strive to improve with each piece, and make every new one better than the last. You might not succeed, but you'll still learn something; at the very least, you know where your limits are. Besides that, do look out for extra learning materials to learn skills from. I'm self taught, so I usually end up reading a lot of books, watching video tutorials, but even you as a student would benefit from some extra lessons if you can afford the time to learn from them.
6) Stay connected
To your clients, to the community. Don't just accept a job and then disappear for days/weeks, and suddenly turn up with the finished product. Your idea of a finished product might not even be what the client wants. Make a point to send Work-In-Progress pieces, and get feedback. If you need to change, try your best. If you can't, say so (but be honest, don't say "can't do" because you're feeling a little lazy). As for the community, it's related to the networking/marketing. Reputation's the main thing that attracts clients, and if you're know to turn out good work on time, with good prices, and you are NICE while doing so, more clients will come to you, and some might even stay with you. My best clients are "long-term" ones that I'd worked with before. I know them, they know me, so we each know what to do to make the other happy about the process and the product, and we both know that if the results are good, we both get the benefits. Cross-promotion is a VERY powerful thing, since you get to twice or more the normal audience, and you'll get unexpected clients from unexpected places.
7) Have fun
Remember, you're doing this "part-time", and art is supposed to be your passion. If you start HATING what you're doing, you are not going to be motivated, and especially because it's part-time, motivation is VERY important for staying on the job (not like full time, which has things like contracts and labour laws and stuff), and because you are your own boss, you're responsible for your own motivation. No point doing something half-baked, and end up abandoning it because you "lose steam". Not going to help you at all, and might as well not do it, yes?