I'm not entirely sure if I'm somebody worth listening to on the topic, however this is how I warmup / play / train.
Pre-Session
Before I start playing I do some fairly rudimentary hand stretches, which i would advise before any long sessions of playing. Doesn't matter how you warmup or train if you hurt yourself and you can't play.
Warming up
When you're warming up, it helps to set a particular goal for your session and what you want to accomplish. For example, I might spend a few days grinding Hardrock for accuracy training, play a session focusing on certain patterns such as chordjacks, LNs, streams, etc. or I might dedicate a session to building speed and play with DT.
Its important to build as diverse of a skillset as you can from the getgo as improving is quite a bit easier when you don't have to go back and grind skills you've neglected.
Some good rules of thumb to follow when training different skills include:
- Start out easy and build your way up. If you jump right in to the hardest songs you can play, its likely you won't be adequately warming up your accuracy. your first few plays should ideally be songs you can S-rank (while still following the theme of what you're attempting to practice).
- Set benchmarks. When i was grinding handstreams, i used Burst Linker - Wafles' Lv.15 as a way to test my progress. When picking a map to benchmark with, its important to aim slightly above your current capabilities without being too difficult to achieve in the near future. I like to use maps I have a score in the high80% range on and I'll use it as a benchmark until I S-rank it.
- Don't limit yourself to ranked maps. There are many great mapsets out there which feature patterns you won't often find in a ranked map which are very useful for practice.
Post-Warmup
After 30 minutes to an hour, I'll either move onto limit pushing or ranked pp farming.
Limit pushing involves scaling the difficulty up beyond what you can normally complete (0.5-1 stars above what you can S-rank). I recommend setting up a "pass me" collection containing maps in that difficulty range.
Alternatively, you can focus on improving your accuracy on plays you're close to S-ranking. If you play a lot of ranked maps this is where the majority of your pp will come from, however the main purpose of this is just building consistency and should not be limited to just ranked map.
An example
Goal for the session: improve stamina on jumpstreams and handstreams
warmup:
4.0-5.0* jackspeed maps (shorter songs, 3-4 maps)
4.0-5.0* Streamy maps (any kind, 3-5 minutes, 3-4 maps)
4.5-5.25* Chordjack maps (3-5 minutes, 2-3 maps)
5.0-5.5* jumpstream / handstream maps (4+ minutes, 5-6 maps)
limit pushing:
5.0-5.5* js / hs maps (maps i haven't passed yet, 4+ minutes)
5.5-?* js / hs maps (4+ minutes, occasionally bump the difficulty up if needed)
The difficulty of maps and the types of patterns you'll want to be practicing will vary from person to person, its on you to assess your own abilities and determine what you need to work on.
tldr
I'm nobody, better advice is probably just to enjoy the game and don't hurt your hands