Q: Is it true that osu! helps aim in FPS games? A: Yes, osu!™, a rhythm game, is scientifically proven to be a better aim trainer than actual aim training programs such as Kovaaks and Aimlabs. The 2D aim of osu!™ translates directly into 3D aim.
No, it doesn't help much at all. I've been playing for 7 years and I still suck at FPS games. It may help your general coordination and reaction speed, but that's only if yours is really bad to begin with. The returns will quickly diminish. Also, osu is 2D, FPS are 3D. Stick to aim trainers or actually play the game you're trying to get good at.
Q: I'm new, do you recommend buying a tablet? A: Yes, tablet will automatically improve your skill. The amount of skill you gain scales with the cost, so buy the most expensive tablet you can.
No, I don't recommend buying a device for a game you just started playing. Stick with mouse for a while, you may not even need to switch to tablet if you find yourself progressing at a good rate. Most higher ranked people do end up preferring and playing better with tablet, but you may not be in that majority. Mouse skills are transferable to tablet and vice versa, it just takes a while to get used to the switch.
Q: Does higher end equipment help? A: No. You should spend an excessive amount of time playing with inefficient peripherals as this will make your cool-factor skyrocket.
Peripherals do matter a lot and anyone telling you otherwise is coping or ignorant. I'd say the minimum you should shoot for is a mechanical keyboard of some kind, a comfy mouse or osu-recommended tablet, and a 144hz monitor. After these points you will see diminishing returns in what you can squeeze out of peripheral upgrades as opposed to just playing the game more. Also see following graph:
Q: How do you deal with nerves? A: By not getting them.
Mindset and lots of experience (play more). You have to constantly remind yourself even during tense parts to calm down mentally and physically (stop tensing your fingers when there's a burst coming up) or you won't play at your best when you need to. Also, I think turning off most in-game elements helps distract you less. For me, seeing combo at the bottom left just generates unnecessary anxiety. Use shift+tab (default) in-game to disable.
Q: What do you think about people who stay low rank on purpose? A: They must be stopped.
Honestly it's annoying to be beat by random mid 5 digit players in multiplayer who're clearly way better than the average person at their rank, but as long as they aren't abusing their rank to join easy tournaments then it doesn't really matter.
Q: What do you think about offline players? A: They must be stopped.
Optimistically they're doing it to get into a mindset that allows them to improve better and that's cool with me. Pessimistically they're doing it to boost their ego by coming back online and setting good scores without increasing their hours and play count which I think is pretty lame behavior. Just own your stats, this isn't COD. Also, half the time "offline players" are actually just cheaters anyways.
Q: What do you think is the most overweighed skill? A: Accuracy. I should be able to get a C FC and still get most of the pp, accuracy is not important in rhythm games.
It's still high star DT jump maps even after the last few reworks.
Q: Should I avoid unranked maps? A: Unranked automatically means bad. Every time someone puts on an unranked map in multiplayer, you should complain about it.
There are a lot of hidden jewels in graveyard and pending. Just as there's a lot of bad ranked maps, there's a lot of good unranked maps.
Q: Tips on how to improve? A: Play Genshin.
This game is not complicated enough to warrant long, drawn out essays and videos that I've been seeing on the subject. I think it can be boiled down to the following but this is purely subjective to my experience and my interactions with the community:
Bad at x skill -> play maps involving x skill
Challenge yourself, but don't overreach or it's not going to help. Someone at 3* level isn't going to improve by playing 7* maps.
Download as many maps as you can. If you only play the same small pool of maps you always do, you'll stagnate. There are plenty of forum posts and reddit posts linking to bulk beatmap downloads out there if you don't want to download one by one.
Don't be stubborn about changing your playstyle, input device, or area/sensitivity. Yes, both mouse and tablet are viable. But for you specifically, which one clicks with you more will vary person to person. Try both for extended periods if you can. I stuck to mouse for 4 years, and hit a skill wall. After switching to tablet, I improved immensely and am still improving with it today. I also switched to a bigger area after about a year, which also helped a lot.
Have fun. Life is too short to be dumping hours into getting good at something you don't even enjoy. I have an abysmally slow improvement rate, but I keep at it because I genuinely love playing this game. "If you think you're going to have fun only when you become skilled enough, you're never going to have fun in this game because you'll just keep pushing the range of what you consider to be good enough farther and farther out of your reach, to the point where it becomes unreachable."
Buy decent peripherals. You're not going to magically gain skill just by getting a mechanical keyboard, 144hz+ monitor, and an expensive mouse or tablet. But while your skill may not increase right away, your improvement rate and skill cap definitely will if you were previously using rubberdome, a 60hz monitor, and a crappy office mouse. You don't have to break the bank to achieve this; you don't need high-end, but you should really avoid low-end.