Keep a food diary. Write down everything you eat and drink to keep track of how many calories you're taking in and figure out what bad habits you need to correct. You'll be much less likely to go overboard if you know you have to write it down. You can also use a food tracking app if you prefer, which may make the process a bit easier since most apps calculate the nutrition values for you.
There's nothing wrong with hitting up happy hour. But when you start to drink in excess, you'll wind up packing on weight in your midsection since alcohol is digested as a sugar, and sugar ultimately turns into fat. Think of a bottle of wine as a stack of cookies — both convert into your body the same way, so you should moderate your intake accordingly.