Can somebody teach me how to do SpAs?
Well, blowguns are pretty great, so shoot anything dangerous and run away. This works especially well becuase you're fast. Blowgun should carry you at least to lair and is pretty useful in lair too.
Edit: so I went to play a SpAs after this and found quicksilver dragon armour on D6. Yay.
Yeah, basically you just run away while pelting anything you can kill with needles/darts/rocks/whatever. This is how you handle most things, saving your more potent needles for big threats like spell casters. Your biggest problem is killing things immune to poison. You can eventually up your damage with Stealth, Stabbing and Daggers (this is fun, but occasionally you end up in a sticky situation when you accidentally wake up something dangerous before you stab it). You can also try upping your damage with spells from summons or high damage spells, but you have to play it by ear based on books you find.
Try to get any spells or effects that let you be safer (ones that can deflect ranged things, ones that let you teleport, that butterfly spell, ones that immobilize or confuse opponents). Your biggest threat is things with ranged magical burst damage, things that might immobilize you somehow or things that have someway to stay close to you or box you in (almost nothing does, but the few things that do can be scary). Try to kill any of those sorts of threats really fast or just get out of their sight asap.
Some things like hydras can be difficult for you to kill because they regen fast and are immune to poison, but just run away from them, you're faster than most threats and can sneak around them later if you have to.
The hardest part about playing a SpAs is knowing not to bite off more than you can chew. Your HP is terrible so if you make a mistake it can feel punishing because you might die almost instantly, but the way the game is setup it is actually one of the easier classes to play as long as you know when to run away.