Hi I've always wanted to do marketing but I don't really know where to start people say do it on market or the items thread bjt I just dont know how do to do can someone explain?

Go on the item thread and read the rules and that should help you. Other than that just win item duels then sell them or trade them.

Okay thanks but i don't think i will be doing any item dueling, im not very good xD

Best advice is try buying on the market items thread. there you usually find items at 90% discount. Even better is to look out for people selling their deac, if they are then look for a few items that you think you could make profit on and buy them then sell them on the market. e.g Buying a Full Aqua set for 1500tc which would leave you with about 300TC profit once sold on the market. What I've learned is not everyone knows about the market thread and rarely uses it and for those people, they don't mind paying extra aslong as they get it cheaper than the Tori shop and instantly

first of u only buy at the lowest price like if item "1" cost 1000tc i wont buy until i can get it at 800tc then sell it again at 1000tc (to get profit)
when do doing that you wanna consider for competition here a example 4 people selling the item "1" at 999tc-950tc-935tc-920tc i wouldn't get involved in that case unless i can buy at the lowest price and wait for competition to die
note:when u selling an item make it always the cheapest of its category even if its 1tc of difference example: item "1" for sell at 1000tc i would sell it at 999tc