You cannot apply pressure on an opening. You apply pressure on a weakness which may or may not occur in the opening.
Sorry there is no magic way to win a pawn in the opening or the other guys would already have been doing that and there would be no point to ever playing the game.
If you have an edge in position you might be able to apply pressure to win ...
It's possible to win a pawn in the opening, but because it is the opening (i.e. heavily analyzed), you can't do it by force. You can only do it if the other side lets you.
The Two Knight's Defense with 4. Ng5 is effectively a pawn-up opening for White, although it's not obvious. You might want to take a look.
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 ...
You have no attack, especially on the king.
Castle 0-0 and get on with the game positionally.
There is not enough material to do any attacking especially the king.
Castle long and White will have the attacking chances such as they are.
You are a pawn up but with bishops of opposite colors. This will be hard to win no matter what you do.