Losing weight before pregnancy

I've been using this app for awhile but this is my first time posting.. Anyways, my husband and I have a 3 1/2 year old son. Lately we have been talking about trying for another baby, but I would like to drop some pounds first just so I can start out at a weight I'm more comfortable with. Can anyone give me some diet/exercise tips that really helped them? I work and don't have a lot of extra time to spend in a gym. But I do have some weights and a treadmill at home. As far as diet, I'm  vegan. I eat pretty healthy already but if I need to start counting calories I guess I could do that :P