If a player has two or more points, he may pot any of the object balls into any of the pockets. If he pots his colour into a corner, he then shows his paper piece to the others and the frame is over.
In cake, it is not allowed to use equipment other than the cue. Shots made using them are foul shots. (It is interesting but one often forgets this rule, resulting in minus one point...) Potting a colour into a pocket having less than two points is a foul if he didn't want to pot it there. unfair play if the shot was deliberate. In this case he is disqualified from the frame being played. The frame is over and there is no winner if no colour remains on the table and none of the players have announced a win (see above).
Apart from these, the normal snooker rules apply. That is, it is a foul to touch balls, to force balls off the table, to cause the white enter a pocket, to shoot with none of the legs touching the floor and so on. The player remains at the table if he could pot a ball "cake-legally". There are no such rules as "free ball", "you fouled, please shoot again" etc. For better players the two-point limit for potting colours can be raised to three.
There is quite a bit of luck involved in "cake", which enables weaker players to win. Of course this game has completely different tactical approaches than snooker, but this is what makes it "interesting". For example, it is sometimes a good idea to pretend that you're trying to pot your colour into the center pocket (making sure you don't, of course). If your colour is no longer on the table (or it wasn't there even when you took the paper piece ;), try to get rid of all the other colours, so that the others can't win. Always try to guess what colour is whose and play according to this, if you can.