Definitely check out /r/lawncare.

Weed and feed work, if used right. Use it per instructions on the bag, if used wrong it can kill nearly anything, including the grass you want to keep. Most require you to apply after it's rained and the grass is wet, this allows it to stick to the weeds and not just fall to the ground.

Be prepared. A few houses ago I used it on my front lawn after moving in and it killed all the weeds - which were about 75% of what was there. Then you need to wait 30 days or so and reseed.

I only use weeder every couple years. My soil is so crappy, mostly a pinch of clay to keep the rocks stuck together. So I seed twice a year, spring and fall. On years I use weeder I skip the spring seeding. Most years we end up in a drought and most of it burns away. It sucks.

I usually just use a generic 12-12-12 garden / lawn fertilizer 4 times a year - less if it turns hot and dry. I get it a farm store. I have also been using Ironite which makes the lawn a deeper green.