Combine medals until you get the biggest medal. Activate X-Medal mode. Chain medals.
Quickshot bonuses can be chained as well. Chains go up to x9 and stay as long as a bonus message is still on screen.
So if you have a chain of 6 messages, a Fairy, normally worth 100,000 points would be worth 600,000 IIRC. The fairies also drop bombs if you don't pick them up or kill them quickly, but then you lose bonus, but it is good for survival. The exceptions are the Sim 5 Fairies.
Technical Bonus is based on how many Micluses and Fairies are rescued. Also, some other stuff I don't remember. I think it's not dying. If you find all Micluses and get kill them, then you get some. I think it's 80% or higher of all uncovered Fairies. So Fairy killing is bad unless there's at least 5 Fairies on the level.
Fairy killing shouldn't be done anyway unless the amount you gain from multiplier would make it worthwhile. The "Killed the Fairy" message does count toward the bonus chain. So if there are 6 Fairies(Sim 5, IIRC. Maybe it was 5), 100,000* 6 = 600,000. But, if you kill a Fairy, you have a bonus chain, so 200,000 *5= 1,000,000. But then there's the 10 points for killing the fairy, but that's minor.
As mentioned before, grazing is a minor addition to score, but if you're comfortable with it, then do it. I doubt many of us will since it's easy to clip stuff when trying. Grazing, does also slow the medal falling, notably used in chaining an X-Medal in stage 1, which I used to be able to do, but will need to practice again.
Edit: Remembered how. Been derping it up though.