The directory submission has various fields that need to be filled and that has been mentioned above.But there are a few rules that need to be maintained so that you don't get sandboxed and also you can get maximum benefit
1)Do link submission manually
2)Choose your keywords and description before you start posting
3)Post only to appropriate directories and place where its ur niche not just everywhere
4)Avoid reciprocal links if possible
Hope it helps you
cheers