Is there a name or technique to easily know to push two or one space for the pawn. Similar to the rules of opposition of keeping a certain distance away or something. Apart from manually reading.
Opposition-like with pawns instead
The pawn you are looking to push is essentially a reserve tempo. When you have nothing to improve the position, you make a move with the pawn, placing Black in Zugzwang. If you do it twice, you win. If you get zugzwang only once, you draw. So if it is White to move, paying h3 forces Kh8. 1. h3 Kh8 2. h4! Kg8 3. h5 and now you have the King on the square he started on but you can swap Rook pawns, stopping the draw. 3...Kh8 4. g6 hxg6 5. hxg6 Kg8 6. g7 and Black cannot go to h8. 6...Kf7 Kh7 and Black promotes to a Queen next move.