the depth you plant a seed is about two times the length of the seed.
always plant in fertile, well drained soil. remember that soil fertility needs to be renewed each year...we do this by adding a layer of compost to each bed.
know the temperature of your soil...some seeds like it hot, some seeds like it cold, and some seeds like it just right.
keep the soil moist as the seed germinates and the seedling establishes roots and leaves.
some plants like to be directly sown into the soil and some do better as transplants...try each to see which works best for your garden culture with that seed.
finally as my friend Matthew Dillon says "There are three important rules for growing: #1 Observe. #2 Observe #3 Observe."