Tips in playing Hardcore league

Need insight.

Don't do evasion as main defense, it is designed that you eventually get hit. It is ok to play dex-based characters, but you need a large life and/or energy shield pool and capped resistances asap. So if evasion is your general-purpose defense you will eventually get hit by something big and die. Evasion also does nothing vs ground dots, so you need some recovery.

Do you have an end build in mind and looking how to get there, or looking for inspiration as a whole?

1. Grind certain locations a few times to get up-to-date gear: Axiom Prison, Chambers of Sin, Vaal Pyramid, Solaris Temple, Mine Shaft where you first learn delve, etc. Any long room which has you fight one pack at a time without a major boss and can be efficiently reloaded.
2. As far as the Labyrinth, Izaro fight is trivial when you over-prepare, but definitely over-prepare, traps and Izaro get some surprising skills and there's the temptation of power to make you try it early. Don't do Merciless Labyrinth until comfortably in maps.
3. Trade is pretty dead, but trade is better than SSF because huge portions of the game aren't made meaningless by lack of use. In softcore, items that drop from uber bosses are cheap, in hardcore they are rightly expensive, but you still have a chance to get them.
P.S.
Use alt characters to get early gems you need as some will not be available until Library act 3 or Lily Roth act 6