I figure I'll give my two cents in regards to the blackjack minigame since there's so many people crying about it.
This is how I tend to play in games that include it, so take it with a grain of salt. Experiences may vary.
1: Hitting anything from 18 or above is asking for trouble. (Not that it's impossible to get something better, just unlikely.)
2: Anything below 15 you wanna hit. Even if you've got an ace, there's little chance you're gonna beat her with that.
3: Having either a 16 or 17 is very tricky. Look at what she's got, and keep in mind the rules on the board. If she's showing a 7 or less, she's likely gonna need to hit.
4: Personally I tend to go for the highest bet possible. If my last hand sucked, I'd go for either half of my last bet or whatever would bring me to the nearest ten if I lose the "current" hand. (That last part is specifically just because I like it when things are orderly like that, there's no real underlying reason for it.)
5: Savescum. If you really don't wanna have to deal with luck or chance in a game, you should be savescumming. This applies to New Vegas, the RDR games, or any other games that include gambling and the ability to save manually. (The abuse of this might end up with you not having as much fun, but that's another discussion entirely.)
6: I don't split. I just don't care to.
7: I focus on one character at a time, finish their story, then move on to the next so that if money's tight, I can sleep it off, then do work on the PC till I got the cash. Dunno if this really counts as a "tip" per-se, but I figure I'd include it just to be safe.
