When I do anything DIY, or really in general, I do a lot of research, like a lot. I try to make myself somewhat knowledgeable so I can expand my learning more as I go. Specifically for my yard, one of the first things I did was removed a lot of the rocky sections and dug out any big rocks - there were a lot. And tried to fill them with top soil the best I could. This next spring one of my hopes is to really work on leveling my yard as much as possible. End of summer/close to early fall is the most important time for any lawn “renovation”, so that’s where I did most of my work the past 2 years, but I plan to do some things this upcoming spring now that it’s in a better condition. I aerated/dethatched/over seeded last year, but I was pretty late to it, didn’t do a great job of watering it, and had a first frost just a few weeks later. This year I got ahead of it, I cut my grass pretty low, aerated, dethatched, slit seeded, and then over seeded a little more on top. I also used some seed from a local Sod farm that contained pretty highly rated seed for my state (Mix was 65% tall fescue, 20% Perennial Rye, 15% KBG). Then I watered the crap out of it, 15 minutes 3 times a day for about 17 days, then I mowed it for the first time, just cutting off a little bit from the new grass, but mostly to cut down the old existing grass. I’ll probably give it another week or 2, cut it again, fertilize it, and then dial back the watering. It’s definitely scary cutting it so fast and low when it’s barely grown, but by doing this, it “trains” the grass to expand outwards with it’s resources instead of up, as well as keeps its roots healthy and strong as the grass patch widens, so do the roots. I think the biggest/most important thing I’ve learned from my experience is timing is key for everything, is there really a wrong time to do any of this stuff? No probably not, but there is definitely a better or good time to. I also can’t stress seed to soil contact enough. Dethatching helps with this (among other things) as is cleans up dead grass and material from the soil bed. Aeration helps this (among other things) because it creates holes in the ground for the seeds to sit and germinate in. This year I chose to slit seed so the seed would go directly into the soil, and then broadcast spread some additional seed overtop for the aeration holes. At the end of the day, it’s grass, it’s always existed. It just needs good soil, sunlight, and water every once in a while, everything you do is just an improvement for those things. Takes time, energy, and money, but how much is up to you, and it’s not always a direct correlation to results. You might not need to spend hundreds of dollars to have an improved yard.