This is actually a good time to start out with some basic lawn care. Right now, put down some fertilizer with crabgrass preventer. Fertilize again (no herbicide or pest controls, just plain fertilizer) in about 6 weeks. Meanwhile, a spray is the best way to control broadleaf weeds (dandelions, clover, etc) IF you have a lot of them. If you just have a few, digging them out manually with a weed tool is as good as anything.
Use a grub control in June or July if you see lots of june bugs around your porch lights. Otherwise, don't worry about it.
Finally, fertilize two more times; in September, and lastly in Oct or early Nov with a winterizer.
That's really about it if you do all that, you'll probably be quite happy with your lawn by end of the year.