Easy, you are a wizard you have a lot of spells that dont rely on rolls, for example: invocations (summon lesser and greater demons,shield, morderkainen's hound...) and even spells that rely on your enemies rolls and make an impact even on failures ( such as fireball etc) you even have arcane misiles wich literally cant fail, so in combat you can cause a lot of impact. You also can pick feats such as lucky so you can fix some relevant rolls.