How to play when you have the tempo


My advice:
(1) Know the move you most want to play at every point of the opening so that when you get an extra tempo, you can play that move. I call those "default moves" (https://www.chess.com/forum/view/chess-openings/determination-of-default-moves-in-a-given-opening). Big downside: I don't know any book that has this information for any given opening.
(2) When you get about two tempi ahead, start looking carefully for tactical moves that win at least 1-2 material points, sometimes more. Again, typically each opening has its own characteristic weak points so that is great information you should learn with each opening, but again this information is difficult to find. Look carefully for forks (especially by queen, knight, or pawn), skewers, hanging pawns and pieces, overworked pawns and pieces, a pin of the queen against the king, smothered mates, the Damiano's type sacrifice of NxKP ...KBPxN, wins of the exchange, discovered attacks, etc.
Hey fellow chess players, I've been playng chess for a while, but it wasn't until recently that I've really started to study and work to get better.
So anyway, Here is a beginner question about openings-How should one play when they gain the tempo after the opening?
This is a common problem that I have seen in my own games, my opponent makes a questionable move advancing his knight or something so I kick it out, gaining the tempo. However, after I have this tempo I don't really know what to do and usually end up making a questionable move of my own. Any advice or example games would be amazing help.