Determine what you have growing and work to encourage that.
Crabgrass needs to be removed manually and completely. Removing the tap root is the only way it's gone.
If you have a "Bermuda Grass" type of lawn, ANY crabgrass control product will kill that as well. Be careful or you can screw it up real quickly.
Read all product safety stuff, the pet you save may be your own.
Lawn type Weed control products only REDUCE the possibility of "weeds" establishing themselves. A healthy lawn will resist efforts of infiltration simply by it's mass.
Overseed bare spots by scratching the surface up rough, seeding and covering with a "Lawn Topper". Keep moist until sprouting occurs. Overlapp edges by a foot or more to blend.
Now is the time to overseed thin spots and add amendments for a richer, more lush lawn in the summer.
If you rent / buy a pluging areator, you can areate the lawn, add compost to amend, Rake/ Roll flat, Overseed Entire lawn, Spread out Lawn Topper , Rake for level, Water throughly.
The dark color of lawn toppers is designed to hold heat during the winter months to help germination of grass seeds.
Damn Kids...Get off my yard!