Two bet sizes: 33% and 75% of the pot.
Use a small 33% on dry boards, and 75% on draw-heavy boards and for value against players who don't fold; also bet big when only your range has many strong hands (nut advantage). Example: with a pot of 10, bets are 3.3 and 7.5, and the opponent needs 20% and 30% equity to call. In a 3-bet pot, even betting 33% on the flop gets the stacks in by the turn and river.