Remember, lots of sun and good drainage is a must. Wildflowers do not like wet or shady ground. Another problem you may encounter is too much competition from weeds. This can be a result of not properly removing the existing vegetation prior to preparing the site. It can also be a result of tilling the soil too deep.
Most soils contain thousands of dormant weed seeds that are released when the soil is disturbed.
Tilling too deep will result in many of these seeds being released. Planting the seeds too deeply will give poor results. When the seeds germinate, the seedling must reach the soil surface to survive. If planted too deep, the seedlings never reach the surface. Trying to cover a large area with too few seeds will give poor results.