What's your budget, what are you looking for? Expectations? Style? Etc.

That budget allows you choose quite a few tailoring shops. But in no way you will get those high end handmade construction that the guys talk about here all the time.

Go jalan2 in Amcorp mall and ask for quote if you are around PJ. If you are in KL, you could go to Pertama Complex next to Sogo. These 2 shopping malls are not that big and houses at least 5 shops between them. Could not recommend any shops in particular. So in some way you have to sort of interview the shop owner/tailor that you are most comfortable with.

About style, your choice is only limited to a regular black suit with some details. Because you want to make use of it for other times like dinner or a night out. There is this interesting website that you can play around with customizing your own suit design.

https://www.itailor.com/design3pcsuits/

So you know what design you need and color combinations. Note what you want, maybe take a pix on your phone and show the tailor you want it like that.

But if budget is really really tight, you can visit this physical shop.

http://www.kinghouseapparel.com/index.html

Save you lots of money. But remember that these are China made suits. Most design is not that nice and borders on being entertainment/ variety host style.  Yes you can buy those designs straight from TaoBao. But you can try them out at their physical shop and see it it fits and works for your needs.