Generally, the fewer decks the better, all other things being equal.
Eight decks is bad, six is mediocre, four is better, two ect,ect.
A dealer standing on all 17s is good, a dealer hitting soft 17s is not as good.
You want to be able to double on any two cards( DOA) and double after splits(DAS). Europeans play a different game, where the dealer does not take a hole card. This game uses different basic strategy(BS) than most games referenced here. I've never played it, myself.
You really need to do some reading on your own. If you keep asking really basic questions, you will wear out your welcome fairly quickly.
If you can't find some books, use the lessons offered at the BJ School on the left of the screen.