While not in Chicagoland, general care is where to start with any lawn from Peoria to Peking.

Under normal circumstances, I'd say get a Logan Labs soil test but I was the last man standing who read them here. Circumstances have changed and I'm no longer willing to do so, but if you search my name, Logan Labs, soil test, and look at the sites, you'll find a place where I do read them (and several others who do as well). It's a bit down the page in Google.

Without that, telling what to apply is impossible and I'll make only the most general suggestions.

One, apply a good pre-emergent (I suggest Dimension 0-0-7) when the forsythia in the area blossom in spring. That should be shortly. While you cannot seed the lawn if you do this, it'll stop weeds from growing, which will be your primary battle this first summer anyway. Let's try to exhaust the soil bank of some of its seed before August and live with it, giving you time to get that soil test.

Mow high. As high as you can stand it. I mow at 3.5", which means the grass grows slower, uses less water, and doesn't shock as easily.

Water if dry, rarely and deeply. Once a week would be nice, an inch at a time if possible (put out tuna cans to check this). A bit more often with a bit less water is fine in very hot weather--every 4 days if it gets absolutely stinking hot, over 90-95.

Spray weeds with any good herbicide as needed. I suggest Weed B Gon--and you may need Chickweed, Clover and Oxalis, or Crabgrass. It depends on the weeds you get. Don't use weed and feed. It's applied at the wrong time, in the wrong amounts, and feeds incorrectly. Spot spray instead.

Feed the lawn on Memorial Day or thereabouts, with any good high-nitrogen fertilizer (high first number, low everything else). And with nothing else in it--no Weed and Feed. No insecticides (most insects are helpful or neutral). No nuthin'.

You'd normally feed again on Labor Day (grass doesn't eat during summer), but you'll want to seed in mid- to late-August.

By that time, your weeds are dead, the Dimension has suppressed out some and killed the babies during spring. Your lawn should be in much better shape. Blank areas should be filled in a little (with any bluegrass in your mix) after proper care.

Pick any good seed, apply at bag rate, water 3 times per day through sprout (up to 30 days if the mix contains bluegrass--which I recommend in Chicago), then back down slowly through fall.

Feed October 1st this year.

As for timing on the herbicide suggested above, wait until the weeds are up and growing. Mid April is when I do it in Texas, but I think most lawns from Florida to Alaska have awakened by then.