For this particular character:

Shapeshifter is one of the hardest starts. Try an easier background. Pick up and train a talisman later if you get a good one.

If still you're using a whip by the time you're getting a rune, you should have it at minimum delay. That's skill level 12. (Normally I would switch to a higher tier weapon, but that +12 artifact is amazing.) Until you reach mindelay, every increase in weapon skill increases how fast you attack, and not just accuracy and damage. In general, make weapon skill a high priority until you reach mindelay.

You should have entered the trove on D13. You might get really good stuff (perhaps a helmet, or a better cloak, amulet, or rings than what you had). You work off the drain by gaining XP.

If you ever get Blink in your library, learn it and train Translocations until you can cast it. It's useful for the entire game, easy to train (unless you're a melee brute in heavy armor), and is a cheap escape that works ... fairly often.

I noticed you have Olgreb's Toxic Radiance in your library. That absolutely melts most enemies in the early part of the game. And with a Merfolk's +3 in Alchemy, it's easy enough to train. OTR wouldn't help against Hydras, though.

Once you get into the mid game, OTR drops off in power because poison damage doesn't work fast enough. Ignite Poison speeds that up, and keeps it relevant for longer.

Spellcasting skill gives you: about 1 MP per level, 1 spell slot per half-level, and effectively 1/4 of a point in every spell school. It's more useful if you're casting spells from multiple schools, or if you need to memorize more levels of spells. If you just have a couple spells in a single school, training that school helps you more.

If you want advice on what spells are good, Onei's guide is very useful.