When DD2 was that age I was following the Healthy Mummy program. It is primarily for weight loss (I had 30kgs to lose) but they also show you what to do for maintenance. I know many (including me lol) are going to promote just healthy, whole foods but at that time with 3 littlies I needed something to 'follow'.

Now though I try and eat as fresh and as basic as possible without denying my love of cooking/eating. If I'm feeling a bit funky I record what I eat for a few days via calorie king or my fitness pal and try and gauge my macro or larger nutrient content to make sure I'm getting enough of what I need. I also try to eat lots of good oils (nuts/avo/oily fish) and plenty of protein.

I also use a magazine a lot called the Australian Healthy Food Guide. Great recipes that are reasonably quick, easy and cheap.