When looking at a position, the first thing (assuming you have enough clock time to do it) is not to start calculating combinations but to identify squares, pieces, and pawns that are likely to be involved in tactics.
First, what pieces or pawns are left hanging - undefended? White's b- and e-Pawns and Black's c-Pawn and c5-Bishop are currently hanging.
Next, which pieces that are attacked are over or underdefended? Everything is aimed at d5, which is attacked and defended three times.
Next look at potentially vulnerable important squares like f2 and f7 and attack/defend if an opportunity exists. Note that Black's Q and B point at f2 and moving the White Knight fails in an attack because White needs a defensive after ...Bxe3, threatening ....Qxf2.
Then look for existing or potential pins/double attacks/skewers and other common tactics.
If no obvious tactics leap out, try to develop pieces and aim them at your opponent's king while keeping your pieces protected. Look for Knight Outposts, creation of isolate and backward pawns, center control, etc.
If you are White, you can see that moving your d5-N out of harm's way can to b5 attacks the undefended c7-Pawn and moving the d5-N to b3 attacks the c5-Bishop, but the c5-Bishop can then exchange with White's e3-Bishop, giving White the disadvantage of double, isolated e-Pawns.
Please guide how can we choose the white's best move in this position. It is just a simple position but I want to know the technique/method to be adopted to find the best move in these types of tactical positions. Which are the lines that we should/should not calculate and Why? I really want to know. Thanks