Getting you lawn in order is not that diffcult. It does take time
though.
Its hard for anyone here to give you advice, there are too many
factors, i.e. location, what sort of problems you have now ect..
A good rule of thumb is:
March is the time for crabgrass preventor (Pre-emergents) It's still
not too late to put the pre-emergent down Lesco as a product for those
who missed the window of opportunity
April/ May Broad leaf killer, kills 99% of the weeds in your yard
(Clovers dandylions ect)
June; basic feed fertilizer
In my area NJ, I do nothing to my yard for the rest of the summer..
Late Sept early Oct. I aerate and seed

I also lime once a month it doesn't hurt if you over lime it.

the following spring, I start it all over. You dont need to aerate
every year, I do it simply beacuse between all my neighbors, we bought
one. so i can do it anytime.

The other thing I would tell you is the quaility of the products that
you put down.. I used Scotts for years, it works well but it's too
expensive for the amount you get. I began using LESCO and I'm getting
more bang for my buck.

Get your weeds under control and your yard should flurish. Get the
grass nice and thick and you'll have less weeds.