My good habits are to use small sprites, No large transparencies, keep the sprite count on screen low, don't Set Dictionary or TextBoxes on every tick, avoid webgl effects effects and I get close to 60 FPS on my galaxy S4, and 50 FPS when using new multiplayer module (working).... testing, testing testing.... requires lots of testing and refinement but it is absolutely possible... the people that have issues are ones that build the game entirely tested on PC and then port to mobile and see a major performance loss. Tablets and PC's are much more forgiving but mobile requires lots of hard work to keep the frame rate up.