However, there is a way you can win pretty much every time. I have the achivement where you have to win 30 times.
The rules are simple; you have 3 decks to fill out and these three decks should be filled out with a number between 21 and 26
You have to pick out 30 cards before you can begin, for this to work the best I'd suggest pick out the jokers, the royal family cards and the aces.
Beside from those three types, pick out all 7,9 and 10.
7+9+10=26
Then you basically discard everything but 7,9 and 10. But keep in mind you can discard one 7 one 9 and one 10.
When you start stacking them up remember you can only stack them 7,9,10 or 10,9,7. 10,7,9 wont work.
Just do this and you'll have the achivement in no time
It's also great in the start of the game, because once you reach Novac you can play against No-Bark and you can probably earn alot from playing against him, which will make it easier to enter the strip with the 2k caps fee.
OH and one more thing.
Breaking the bank is real easy aswell.
Just go to a roulette table save game, bet 200 chips on either red or black (50/50) and if you lose you can just load back to before you lost. Keep doing this and remember to save after each time you win 200 chips. Oh and every time you load file back, you have to wait for a minute, so it's recommended watching for example a movie or a TV-show while doing it.
If you're having troubles with this, please comment below and I MIGHT be able to help you!