I agree with Merlin, and add that having a cheat day can help immensely, especially when you are just starting out. That way when you have a massive craving for something (and you will, eventually) you can either indulge straight away and get back on track tomorrow, or force yourself to wait until your appointed day. That doesn't mean you stuff yourself with junk of course; you should still be limiting yourself to a serving size.

On that note, us Americans in particular have no concept of what a serving size actually is. I thought I did until I started actually following it and realized I regularly ate 2-3 times what was written on the package. I also bought a food scale that I use for cooking that has been eye opening in its own way. One serving of pasta looks way different by itself than part of a huge bowl.

Right now I've set myself a fitness goal and a nutrition goal because overhauling my diet at the same time as all the other things I'm doing right now would be insane. My fitness goal is to work my way up to 300 minutes of exercise a week. That's 30 minutes a day, every day. I'll probably end up going for longer each day so I can get a rest day in there. My nutrition goal is to basically stop eating candy. It's my major downfall even though ironically I don't even like it all that much (I prefer savory foods). If I buy candy I will eat it, whether it's a small bar or a huge bag. The only way I can break this addiction is to just go cold turkey. Eventually I will get to a point where I can hopefully work it back in somewhere as say an occasional dessert treat or whatever, but for right now it's just too easy to indulge.

That said, it's time for my workout.