First of all, do you know which precise cosplay you wanna do?
Then I would advise you to make a list of all the character's clothes and features (hair colour, make-up etc). For each of these items, you have to choose if you want to buy them, make up yourself or find something that looks like it. Example : if you cosplay Janet in the Rocky Horror Picture Show, when she wears a pink dress. You can buy a cheap dress online, or sew one yourself if you have the ability or find a pink dress which is a bit like the real dress. Thus you have to know from the start if you're going to pe picky, wanting every detail to conform to the original. Feel free to ask help to people around you to help you gathering props, or sew or anything. Well, that's seems like pretty general advice to me, don't know if I answered your question :) I've done a dozen cosplays so feel free to mp with me if you want to speak about YOUR cosplay in particular
I recently got interested into cosplay. I saw many amazing cosplayers and i wish to do a cosplay for next year's con in my country. I'm so excited and can't wait to happen(๑•ㅂ•)و✧. I have many months to organize everything but where should I begin?