I am sorry to say that the answer is "no", there is no "easy way" to apply pressure and win a pawn in the opening, otherwise, at the top level of chess, the game would be won every time. That is what positional chess is about: You gradually improve your position until the opponent can no longer save all of the material.
A theorem of chess is that you must be better to "attack", or even to apply pressure in a specific area of the board, you have to be better in that area. Being better in a specific area of the board, or the whole board, is a result of good positional chess on your part, or bad positional chess by your opponent.
Usually, players do not start getting a good grasp of positional chess until they are about 1800 over the board (not just online).
Probably the easiest way to win pawns is to cram thousands of tactics problems, and get better at those, so when your opponent drops material, then it is easy to see it, and take it.
I am not going to get into a long explanation of positional chess since there are currently 374 other questions about it, and I know that I have discussed it at length before, but I will leave you with one link to a question I answered.