There are very few seeds with a dark requirement. Assume everything needs light unless you specifically know otherwise. Don't kill shade lovers by placing in full sun. Many seeds have a dry storage requirement that prevents them from germinating prematurely while they are still attached to the parent plant. Indeed many seeds will not germinate at all if sown too fresh.
Some seeds germinate best after several years of dry storage.
Do not fall into the neophyte trap of insisting of fresh seed only. Warm germinators-These seeds usually germinate after a period of time at around 70 F. Most are easy to do under lights or in a warm greenhouse. In general, they are quick to germinate, but a few species with hard seed coats may need scarification or extended time at 70 for bacteria to break down the seed coat. In general, this is a slow process that takes from 1-6 mo. 5. These are usually seeds of plants that bloom early in the season.