Throughout this game you had the option of opening up key lines with X. d4. That would have given you a nice advantage, really. If you played 6. d4, you're going to force a few trades, open up lines for yourself and put black in a defensive position. Push the e pawn after that sequence and black is in trouble.
Also, if you see a hole where an opponents knight can go that is easily defended by black, one of your priorities is to take that away. Knights need supported outposts.
I corrected my post for two typos that meant two illegal moves, lol. Hopefully it's clearer now. My bad.