Apply top dressing in the fall, before the first frost. If you miss this window of opportunity, apply the top dressing in the spring, after you mow your lawn for the first time.
Mow your lawn before applying the top dressing. This allows the compost to settle close to the soil, where it provides nutrients.
Rake the grass clippings before applying top dressing. Even if you don't normally remove grass clippings from your lawn, do so before applying top dressing to allow the compost to reach the soil.
Dump compost around the lawn in small, manageable-size piles. Use a wheelbarrow to spread the compost around, so that you don't have to rake out large piles of compost over the entire lawn.
Rake the piles to spread the compost across your lawn. Ideally, the compost should be approximately 1/2-inch thick.