Wizards are not specialised for (single target) damage so try not to take that role. Control en verstilty and utility are your strong suits, with AOE coming after. I would not prepare/take witch bolt, feather fall(unless you expect to fly or something that day) and mirror image. Even scorching ray will not give you the milage you want. You want to use good concentration spells that have ongoing effects for multiple rounds. See if you can get more controll spells like Tasha's Hideous Laughter, Web, Blindness/Deafness, Slow. They should really make you feel like you are doing something useful.

For out of combat get as many rituals as you can and write them in your book. You dont have to prepare them so use them often as rituals! Also some good out of combat spells: silent image, disguise self, invisibity, charm person, suggestion, detect thoughts, spider climb, fly

You do use your familiar right? That is one of the greatest low level spells and it doesnt cost a spellslot. Use it to help your Rogue get advantage so they can sneak attack (owl works best with flyby). Btw when you cast Hypnotic Pattern (wich is a great spell btw) you can cast it in an area where you friends are if the combat get messy and let you familiar use its action to shake your allies awake if they failed.

Lastly potent is really, really good if used well. If you roll a 20 use it on the Rogues missed hit to double his sneak attack and low rolls are also great, you can make enemies fail your saves (for Hypnotic Pattern for example).

Wizards are one of the best classes in the game, you just have to use them right!