You swing a sword twice in a turn, so why not a spell. Let’s give you a little gift from your old friend your patron….
Prerequisite: level 12
Each turn as a bonus action you cast eldritch blast if you cast eldritch blast as an action.
How about something nice for the warlocks out there….
Power from Power
Prerequisite: 7th level
You can draw power from magic items. If you have a weapon with a magic modifier like a +1 dagger, you can add the weapons magic modifier to your attack rolls for your warlock spells.