@donostrilssmell I am still not sure I get you. As a beginner I might be wasting a lot of time calculating pointless lines but I guess it is something I have to do to get better and not do it as I improve.
If you mean what @stiggling said, then it makes sense. Trying to brute force through all positions is not possible. What I have been doing so far is looking out for certain things that might indicate the presence of a tactic, such as an open king or overworked pieces, pins, and critical squares. In such cases I spend quite a bit of time calculating as much as possible. Otherwise I just play the move that looks logical and is not terrible strategically (like blocking an undeveloped piece)
Back to Basics: Tactics by Dan Heisman (2007)
I'd start with that book for tactics rather than on-line tactics trainers or the Polgar book. Keep going through it until you can solve all of the problems more or less instantly.
Started with it and about a sixth of the way through. Nothing very interesting so far. But I do like that there is quite a bit of text rather than just diagrams as is the case with the Polgar book