Initially, your most important job is to make sure that the lawn area is relatively level and drains properly.  If the area is small, you can do the job yourself with a shovel and rake.  For a larger area, though, call in a professional with specially designed graders to smooth things out.  When finished, the lawn should slope away from the house slightly (about one-eighth to one-fourth inch per foot) and be contoured so gentle swales conduct excess rainfall to a lower grade.  Watch out for depressions--they'll become waterlogged when it rains.  If you have a high water table, it may be wise to install drainage tiles.

For steep slopes that can't be graded (more than 35 degree incline ), consider installing a retaining wall or plant the slope with a ground cover.