I have played many games of Chess, usually opening with either a Spanish opening (e4, K f3, B b5, then castle king) or fianchetto opening (g3, B g2, k f3, castle) but today I got bored so I tried the queen's gambit, another popular opening (d4, c4, e4 if accepted) which is described as one of the best openings, but is so overrated. If anyone accepts and plays Slav defense, their is literally nothing you can do.
Anyway, use Spanish, probably strongest opening.