If you’re already overgrown with dandelions and clover and you can’t use weed killers, what you can do is wait until sometime in August and then kill it off. Spread newspapers all over the lawn and then cover it with black plastic. In about 3-4 weeks, everything will be dead. Remove the plastic and rake up whatever newspaper and dead weeds are left. Till the soil (you may also need to treat your soil if the pH isn’t great), seed it, cover with straw and water daily. Ideally you will want to seed in September since the chances of weeds infiltrating are much lower then. You will have to be vigilant in removing by hand any weeds that come up. Dandelions are actually the easiest weed to get rid of because they are very visible and as long as you pull them up by the roots before the flower turns to spores, you’re all set.
Decent advice, but I’ve never heard of the newspaper and straw routine.
We purchased a house a few years ago where the people that used to live here let it go (sounds like your place actually). What we did, was pull as many weeds as possible with one of those dandelion pullers, then put a good 4" of fresh soil across our lawn (don’t buy the bagged stuff as it’ll cost you a mint - get it trucked in).
We raked it and rolled it flat, then seeded with a top quality lawn seed - don’t cheap out as it makes a HUGE difference.
We have a patch of lawn that runs along the side of the house that got dug up by an excavator that came over. We’ve debated about turning this patch of earth into a parking lot and getting an RV, but we couldn’t make up our minds. I needed to do SOMETHING with it, for the dirt we put on top and rolled was starting to get washed away with rain and wind, so I told my wife to pick me up some CHEAP lawn seed as it’s a small strip I don’t care about.
She picked up some shat from Walmart that was sooooo cheap!
Long story short, the lawn that grew looks like a pile of crab grass and disgusts me every time I see it (every day). I wish I could rip it up and re-do it, but I don’t want to spend good money after bad on this little patch.
So my advice on the seed is don’t cheap out and get the best you can afford.