My thoughts and advice on opening a new restaurant in this day and age would be - location, location, location!
Do as much market research as you can, being specific with what your type of restaurant is going to offer. Nowadays customers like to feel like they are getting a bargain or an offer all the time.
Think about what you can provide and how you can stand out from the rest of the restaurants in your area - should offer big portions or should you do incredible desserts (something that will make customers remember you).
Make sure you negotiate a great rent with your new landlord and ensure you get everything checked with a solicitor. There is lots of advice/opinions available and I could write down, but at the end of the day it all comes down to the 6 P'S - 'Proper Planning & Preparation Prevents Poor Performance'. Do them, and you shouldn't fail.