Hello,

Good soil contact is important. Once the seed is wetted it is important to not let it dry out, even if that means watering it when rain isn’t expected. Seed should be fresh and not too old, or lower germination will occur.

So, you are right, a good raking before you seed, and perhaps a top dressing of a thin layer (1/4 inch) of compost would be in order. On a sandy soil you should get a soil test so you know what your organic matter percentage is (you want about 5%), and how much fertilizer is needed. 

Here are some References for you that can be helpful-especially the first one-

https://www.canr.msu.edu/news/tips_for_reseeding_lawns_in_the_spring

https://homesoiltest.msu.edu/get-started

https://www.canr.msu.edu/news/tips_for_seeding_lawns_in_september

https://www.canr.msu.edu/home_lawns/

http://www.msuturfweeds.net

I hope this  helps. Thanks for using our service.