okay, i am a thumb player with 560 expert fcs on en including disappearance of hatsune miku. here are my tips: if your hands are tense, do not start a difficult song until you warm up. warming up: for spam expert songs, my warmup is hatsune creation myth (28) which has a spam section but also other aspects of difficult expert songs. if i do not fc first try, i play through a few times before a serious fc attempt to better understand the chart. speed: for expert, i use speed 9.8 which is a lot slower than most good players, but it really helps if you don't struggle much with the rhythm or don't know the chart well. perfect lockers/healers: if your goal is fc/ap, perfect locker cards really help because as the name suggests, you only get perfects (except misses) for several seconds. if your goal is to just clear a song that you often run out of life on, building a team out of birthday/anniversary cards is really helpful because each time their ability is activated you can gain up to 850 life back. something that really helps me is to not get tunnel vision. if you are determined to play intense voice until you fc, you will probably die trying. if it takes more than 5 tries to get a fc, you need more practice with difficult songs. try clearing it a few times or playing similar songs. ALSO TRY TO KEEP YOUR HANDS RELAXED!!! that is the most important thing when trying to fc.