Yes ... correct layering of your clothes would be essential.
Effectively you would need 3 layers (Top) and the below are generally worn in sequence. For bottom, 2 layers would be just fine.

1. Thermal
2. Normal clothes / Long sleeves
3. WindProof / Heat

Thick clothes does not mean you are adequately protected against the cold. I disagree that Korea isn't cold as it depends on which part of Korea you are talking about. Seoul has a colder weather as compared to Busan in winter. Busan is a bit warmer due its location to the coastline/sea and being more south in the Peninsula. Peak of winter in Seoul can get as low as -18 or -20 degrees C and the wind just heightens the cold weather more.

On the subject of using your credit card and then presented in dual currency payment, it happens everywhere and not only in Korea. It is not a scam but merely the system way of allowing you to choose in what currency that you wish to pay. One thing good is that you know roughly the converted value of your purchase as shown on the terminal.

To @bearbear claim that it is a scam  ... it is not nor does such exist and I disagree such misleading info. Just that the system uses the current local interbank rate which may not be favorable to you. Sometimes the converted currency is better ... I had encounter this experience using my card back in Thailand several years back. However with our currency fluctuating so much ... it is better to use the local currency (which is KRW) instead of using MY rates.

To give @bearbear credit ... yes. No such thing as your cc is not accepted as long as it is Visa or Mastercard. Additional 1.5% is charged on top of your overseas purchase (Non MYR). Visa and Mastercard international interbank rates may marginally differ thus it is not a big deal.

Is insadong still the go-to and cheapest place for souvenirs? or got anywhere else with better deals ?

ooo thanks! just random cheap souvenirs hahaha.

____

anyway need some spoonfeeding. really don't have time to plan a proper itinerary. So here's a rough one. Will just follow the flow:

Day 1: arrive at incheon about 8.30am. then check in at sinchon hostel. will vist ewha uni in the morning. afternoon bukchon hanok village. can spend whole afternoon here? or can squeeze in one more place? at night will be at hongdae area.

day 2: morning at noryangjin fish market. suggestions for one more place to visit in the morning? will probably head to ilsan city after lunch for my conference.

day 3: full day at nami island. at night.. myeongdong or gangnam? 

it's the university itself not the shops. well the overall architecture looks pretty. nice for photo taking i guess    yeah my 1st day is on a friday. got a korean friend to bring me around should be fine i guess.

nope. attending a conference.
ahh. don't plan to go nightclubs hahaha.   

Can visit yonsei as well I guess. Just next to ewha. 

Lol. Clubbing not my thing

which club did u go??

the last time i went is Club Answer at Gangnam. amaze ballsss 

https://www.facebook.com/THECLUBANSWER/
recently they have this free entrance thingy for foreigners..wow.

last time need to pay one..we paid like around rm100 for entrance with free drinks..coz its weekend.

wah u so powerful?   staying in korea?

thanks for the advice.

I might visit Korea in December. Don't think I'll be able to learn much korean before I leave. I only know anneonghaseyo and kamsamida.

29th Oct
Myeongdong
Namsan Park
N Seoul Tower

30th Oct
Gyeongbokgung
Gwanghwamun
Cheongwadae
Bukchon Hanok Village
Insadong
Gwangjang Market

31st Oct
Hongdae + Trick Eye Museum
Sinchon
Ewha
COEX Mall + Aquarium
Dongdaemun
Cheonggyecheon Stream
Gangnam

1st Nov
Namdaemun
Lotte Mart
Itaewon
Noryangjin Fish Market

2nd Nov
Namisan Island
Petite France

3rd Nov
Back to KL

Can anyone please advise if my itinerary is okay?
Thank you very much in advance!

look like lotsa foreigners? your cam no get splash? 
you tell me which popular destination that have less PRC visitors? 

that is why famous attractions usually have PRC.. there are some blogs did intro good places.. local blogs hehe

yeah lo.. btw, what i mean local is korean blogs not m'sian blog. sorry for confusing 

you are working in korea? good la can go hop around frequently to those nice places    intro more places to me. eventhough i frequent to korea but i feel the changes are too fast. can't keep up that much unless like you staying there la.. but if you are working, also don't have much time as don't have much leave or holidays like msia. if you are a student than different story 

got changes?
such as?

as mentioned by koonghx high turnover for shops / restaurants. then always pop up new places for drama fanatics 
yeah i agree. i knew about this bak kut teh restaurant. no bother to try also.    have you try?

yeah. this is what i'm thinking too. i tell my friends to try it out and bring them to try again when they came to Msia. for them to compare 

is alright. i know to read hangul. beginner level only lolz. ewww.. i dislike sundae.
yugane and andong jjimdak is franchise restaurant and is no doubts people will recommend it. if i'm not mistaken, they have branches out of korea. btw, i like jjimdak but is from andong or from other restaurant. it's way delicious than the andong jjimdak restaurant. this andong jjimdak price is quite expensive    oh yeah also the 토속촌 삼계탕 and others for me is over rated as well but it's full with tourists cause famous. however still have some local working adults frequent the restaurant also

ewww...  people should stop this meat consumption.. also i think i read that due to animal right, younger gens of s.k consume less of this type of meat?