My rules that I follow, that in the long run have served me well (don't get greedy).
1. I bet the min until I win the hand and the dealer busts, then I increase my wager (hoping I hit a streak and increase every bet even if the dealer doesn't bust, as BJ is streaky). If I push or lose, back to the min.
2. I follow the rules to the T. Rules
3. Exceptions to the rule. I strongly believe at least 1 card must be taken by someone in a hand, so if a dealer is showing a 3 and I have 13 and no one is going to hit, I will hit (first I say sorry to the table).
4. If people at the table don't know the rules, leave
5. If players are jumping in and out, I leave
6. I believe you need a certain number of people playing the same spots for streaks (yes, I know I can't prove this as everything is random, but it's what I prefer). If we start losing, I will sit out or play two spots to change it up.
...and that's it.
I've sat at a BJ table and bet $15 for an hour, breaking even, down a little, dealer busts on your win (maybe a double down), I'll chance it and up my bets to $30, if I win, the $50, if I win, a $100, then maybe scale it back, but jump back up high if the dealer busts again. In a matter of 5 min, I can turn a roll of $200 to $700-800 if you're patient (and lucky), but usually can increase it to $400 then cash out.
Lastly, don't feel bad walking away at a high note. I've shocked the table when one a hand I'll end up splitting, double and win a few hundred on one hand and then cash out and whatever is left over continue better. If I lose it, walk away...