If you get a chance to repeat the same positions, come armed with ideas looked up from databases or Fritz suggestions. If moves aren't popular ie non-book, it's often because they aren't very good. Development systems can help, for example in the London system as White, you would play d4, Nf3, Bf4, e3, c3, Be2/d3/c4, Nbd2, h3, O-O semi independently of what your opponent was doing. You plan is to set up a coordinated structure. It can become a problem as to what to do when you run out of nothing moves to play. Even as above, you've got two rooks and a queen to place before anything really needs to happen.Peter Webber wrote: One of my biggest playing problems is of knowing what do when players like this play unrecognisable openings or deviate from standard openings after a few moves.
The Petroff has a reputation for dire and boring chess. Even if that ultimately becomes a successful style of play, a bit of excitement doesn't come amiss.