I can't get past ~150.000 points. Is there any magic trick or is it just getting long fever times?
With a x26 multiplier, your goal should be around 25k per island. You need to keep fever for the entirety of the first island and before landing on island 2 you should be nearly 30k. Try your hardest to touch the clouds as often as possible during fever as well, it will be over a thousand points each.
There isn't much more to say other than keep your fevers as long as possible. If you're less than 75k after reaching the 4th island, just restart. You'll have the first couple islands memorized quickly (until the next day). Might take a couple days, but you'll get there.
If you're really pushing for a high score, it comes down to fever mode and speed. Your score increases twice as fast when you're in fever mode, so you need to be in it as much as possible. Typically, if at any point I lose fever mode on the first three islands I'll quit and restart.
Second is speed - the further you get, the more time you have to rack up points. This means not taking chances, and using speed coins whenever you can. Typically, if at any point I get stuck crawling along I'll quit and restart. This usually means that if I end up playing a game to its completion I'll run out of daylight on the ninth or tenth island.
Finally, try every day. Some days you'll get an easy game, some days it'll be hard. If you just can't do that well on any given day, don't worry about it and pick it up again tomorrow.
As a point of reference, by top score is 331516 on the x30 multiplier.