If you want to ron/zimo with pong or chi, you must fulfill any Yaku. Here are the Yakus you can use if you already made pong or chi in the game.
You have 3 
It depends on the position comparing to the dealer. If you are dealer, you should collect 3 
Like soccer, one mahjong game has 1st half and 2nd half. In the 1st half, you should collect 3
You only use 
Only keep one kind of three basic tiles. If you want to win with 
Keep one pair and four triple, for example:
All the basic tiles you use must be the combination with 1 or 9. Honor tiles can be kept but without honor tiles you'll get higher score. For example:
You have 3 straights as 123, 456, 789 of same kind of tiles. Notice, even you have 1-9, it won't be valid until they are straights as 123, 456, 789! For example:
You have 3 same straights in different colors. For example:
You have 3 same triples in different colors. It's very difficult to finish though. For example:
