MumsGarden.com

If its veg seed, then its beneficial to mix compost into the soil, firm it down by walking over it, then give it a light rake over. Leave for a couple of weeks before sowing the veg seed or if planting small veg plants /onions/garlic/potatoes then they can go straight in , without waiting.
If sowing flower seeds then there is no need for compost unless your soil is poor.Shrubs and trees like a small amount in the planting hole.

It’s been raining for days on end, here. Yesterday I went out in the drizzle to transplant some marigolds, and after it was all said and done, I watered them in simply to make sure that there was soil touching all the little hair roots. Seems silly, with all the rain that is continuing to come down, but necessary.
With grass seed, if you’ve sown it on wet ground, chances are it’s going to germinate quite well. Unless it’s raining every day, though, you’ll want to water it. It must stay moist for at least a week to 10 days. And even then, you don’t want it to dry out severely.
Here is a site that may help:

Aerate !
You must either hire a machine to do this or use a garden fork every 6 inches. Also, spread sharp sand on the surface before sowing seeds.

fertiliser and fresh seed dont mix as the seeds germinating may burn due to high fertiliser content so by spreading it prior it weakens as it dissolves in to the ground