Oh god if i had a nickle for everytime people asked this question. Anyway:
1. (The best way, in my opinion) Make textures. There are tons of tutorials out there, and when you have some good texts, or a full set, just sell it.
2. Play the market. Buy items in the Market for a low price, then sell for a higher price.
3. Win games. In official servers, the servers that have the 'skill level' before them (beginner, semi-pro, blackbelt) you earn 10tc for every win.
4. Buy the tc, you can use paypall or a credit card for this in the shop.
5. Buy a booster, this increases the number of tc you get per win, in every server. Also found in shop.
6. Do surveys, you might not trust them, but most of them work from my experience.
Above all, DO NOT BEG. It is very annoying to many players, and against the rules.