Tactics are really important on amateur play. Perhaps the most important thing. If you know a few basic principles (move each piece at most once in the opening, control the center, etc), and you can spot tactics, you will reach a quite high level. Heck, even ignoring strategic principles at lower levels, as long as you have good tactical vision you will go quite far ahead because the opponent will make mistakes.

There are not always "tactics" in chess games in the sense of having a move sequence being considerably better than any other one. Nevertheless, when there are, there are factors that limit your opponent's choices and one of these factors is a check.