Running restaurants is about so many priorities; great staff, service, atmosphere, marketing and quality of food and drink, it's akin the plate spinning with so many things to think about and prioritise all of the time.
Yet, the one thing I would say to always make sure you focus on is the numbers, the most boring bit for most restaurateurs but so essential. I have always been a customer facing sort of operator and marketeer and found the numbers to be necessary but relied too much on other people.
Engage in the numbers they tell you a very important story - I learnt the hard way!