Advice on Arcane Trickster - eviltoast

Hi all, I’m not sure if I’m playing Arcane Trickster wrong, or of that subclass just isn’t for me, so I’d love some advice.

I’m level 4 now, and I find myself never using my spells in combat. I love trying to figure out the best ways to gain advantage for my sneak attacks, but since all my spells take a whole action to cast, I never feel like they are worth using for this purpose, when I can try to hide or go to an ally to help them fight in melee. Is there some neat way to use Arcane Trickster in unison with all the sneaking and backstabbing, or do the two objectives not quite work together?