When I get matched in the app, sometimes I can tell by the avatar or the name if I’m up against a high level player. But not all high level players use Recycling Station, or Yacht, as their avatar. So if that doesn’t give them away, one of the biggest signs I’m up against a strong player is the way they play their cards, particularly their trade cards.
Imagine the row looks like this in the early/mid-game.
Fleet HQ / Cutter / Battle Pod / Defense Center / Blob Wheel
When I started playing (and often still now), if I had 4 scouts on a row like that, I’d click “Play All”, then take the Cutter, then probably the Battle Pod if nothing else good came up.
But what I notice is that higher level players will often play out their turn like this: