1) The short answer is "someone who will fold a lot". Some factors that make this more likely:
- Villain has a wide preflop range (e.g. villain opened from CO or BU)
- Villain cbets a lot of his air
- Villain doesn't rebluff with his air
- Villain folds some semi-strong hands to a raise (e.g. villain is weak-tight)
- Villain has a high 'flop cbet-fold' stat
2) As a general rule you want to bluff raise boards where you would raise a lot of hands for value. So on J
T
8
you could be raising JJ, TT, 88, JT, T8, Q9, 79 as well as very high equity draws like A
Q
, K
Q
etc. As a starting point, a bluff:value ratio of between 60:40 and 50:50 value is hard for villain to exploit.
On dry boards you are usually raising less value hands partly because it's just harder to connect with dry boards and partly because we often slowplay sets on these flop textures. However, if villain is a level 1 thinker, these can be great boards to bluffraise as it's much less likely he has a hand that can continue. If you aren't sure how villain thinks, try flatting hands like AK preflop and x/ring dry boards when you connect. Don't worry about missing value when he has AQ/AJ... NO-ONE folds a pair of aces on the flop. Ever.
3) The most accurate stat is 'flop cbet-fold' or 'fold to flop raise' (I think HEM2 changed the name, but w/e). If it is above ~56% your bluffs should show immediate profit. Even so, consider villains positional opening range as well. Just because villain bet-folds the flop a lot in general doesn't mean you can attack his UTG opens with abandon. If you don't have a good sample for flop cbet-fold, then attack guys who are opening wide and cbetting a lot.