I've been considering my return to Gems Swap. I used to be pretty good the game. Here are a few tips on helping you improve your game.
1. Probably the most important tip is learning how to play the board. How you observe the levels will make the most impact on ppts per click you make. It's good to practice spotting a move then while you are moving your mouse look to the other sections of the board.
2. Maintaining while building is critical. The thing to remember and take advantage of is collapsing at the top decreases the odds of loosing potential points. Clearing lines at the bottom is far riskier as it can clear scores earlier but in it's aggressiveness it can turn dead area in opportunities. It does a lot to the board but that usually means it'll take more time to reassess the landscape.
3. Patience. Try to go for 4 cubes it'll take some practice but look past the minimum score opportunity. This will kinda translate in a lot of things you do. Also keep an eye out in between point animation to find what opportunities you can stretch a little wider.
4. Clear corners first. Take as much time as you need. The center of the board is very opportunistic and the top will often clear itself on accident.
5. Having good placement. If you only need 1 more line cleared and the set up is made run the clock down by playing in safer area to rack up points.