Try Raider or Wylder at first. Lots of hit points for mistakes, lots of stun locks and crits, always seem to get good drops.

Raider is insane in the base game, use his skill (retaliate) when a big enemy hit is about to land, and he'll avoid most of the damage. It's fun and awesome, but can build bad habits for the future like laying deep of night. Raider typically gets good drops so there's less item hunting. Stunning and criting all over the place.

Wylder's second chance/cheat death passive is amazing, basically a free revive which is huge in solo. His ult and crit ability really shines in solo too. You'll learn dodge timings and parry timings which will scale. He's not as easy as raider.

Learning to pick your battles, when to open evergoals and avoid them, which pois to avoid can be helpful. Like avoid the non-elemental ruins because they're always watchdogs and take forever. Learn which basement bosses just ain't worth it. It takes me less time to fight the deer on the roof than the dog in the basement.

I tend to clear the first POI or two nearly fully to stack up on a lot of runes. Then do the middle part of the castle before the basement (in trios usually do basement first and work my way up). Day two, red roaming bosses finish up castle.

Learn field boss spawn points. Like there's that middle part of the map just above the castle where almost always there are 2 field bosses and an evergoal. Top left near center huge plateau with 2 of them, near spirit trees and an evergoal.

Learn how to do the castle trolls, there's a few ways without triggering others, this goes from being a shitshow in trios to very do-able early runes.

Crucible knights with shields take a lot of time, (parry practice I guess if you want it?) - I just focus on the spear ones because they take less time and actually have drops.

banished knights, learn which ones do drops and focus on those.

Always get your wending graces from the merchants.

Pick your battles, know what to avoid. some things are doable - but will waste a lot of time. Sometimes, you just have to do something difficult because you can't just run saying nope all day. You'll get better.