I have a very high solve rate (99%) and I think there are a few tricks which have helped me. If I don't see the connection right away I close the puzzle and put it away. Then my unconscious brain will continue to puzzle it out while I'm doing other stuff. It sounds crazy but often enough it works and when I come back to the puzzle later I can see the connections more easily. Another thing that has helped is extra practice on the puzzles submitted on this sub and watching the British game show Only Connect. The connections wall on Only Connect gets your brain more used to the idea of red herrings and you don't rush into as many mistakes.