Your wildflower site should have at least 6 hours of sunlight per day. The exception is the Partial Shade Wildflower Mixture that will do fine with less than 6 hours.
Mixing the seed with an inert material such as sand, sawdust or cornmeal makes even seed distribution easier. It's important that the seeds come into contact with the soil. Raking them in to prevent the seeds getting blown away is a good idea but go no deeper than 1/2 an inch.
Overwatering and fertilizing will benefit weed seeds more than the wildflowers so it's better to let nature take its course. Some watering to keep the top layer of the soil moist is a good idea if rainfall is not sufficient.