This app was mentioned in 4 comments, with an average of 1.75 upvotes
Beating Expert for dummies:
0. Adjust your device timing.
1. Set speed for expert on 9.
2. Use many healer and build stamina based team (skill name have yell on R cards), high rarity team is advised because they have more stamina.
3. Buy Love Live albums and put them on your phone, listen everyday.
4. Play using your index finger.
5. Sit on comfortable chair and put your device on table.
6. Put your device on stable and sticky surface i.e. on an anti-slip mats.
7. Practice a lot, hear the song a lot, hear the beat.
8. Find some reference on Youtube/Niconico/Google. keyword: (song_name; in English or Japanese) (difficulty).
9. Install スクプラ / SUKUPURA apps to practice.
10. Try Aishiteru Banzai EX at first try.
Something like this should really be pinned somewhere on this sub, it'll surely help newer users a lot.
Thanks for your effort in making this!
EDIT: You might also want to add SchFesPractice and this app, since both are definitely useful for practicing difficult song charts without wasting LP.
Here are a few alternative apps currently on the play store:
The first one I have installed, and besides poor quality on a few of the videos, I've had no problems with it.
Haven't tried the second one.
Unfortunately there aren't any working ones anymore as far as I know. The closest you would get is probably by downloading a practice app (1 or 2 for Android or SchFesPractice for iOS).