Nails

Kory
I am attending an event at the end of next month and I want my nails to look amazing. I used to have gel then an acrylic overlay but I took them off several years ago. I tried shellac but I didn't keep it up. Usually I go to the drug store and pick up some press ons. I had great luck with them for a while but lately they haven't been settling right. 
What should I do to them? I want a French manicure.