Tip #1
Now is the time to start applying pre-emergent to the lawns and garden beds.
Solution
80-85% of all weeds come from seed, for best results, apply when you see Forsythia and Lilacs just about to bloom.

 http://www.preen.com/videos/how-preen-prevents-weeds

Tip #2
Start mowing as soon as the grass turns green and begins to grow.
Solution
Set your mowing height to 3-3 ½ inches, as taller grass develops deeper root systems. Mow often enough that you are removing ONLY a third of total plant height, this will reduce the stress on the plant.

Tip #3
Divide and transplant summer and fall blooming perennials that had poor flowering, open centers and floppy growth.
Solution
Begin as new growth appears, typically less than 3-4 inches of growth. Use a shovel or garden fork to dig out the clump and use a knife to divide the clump into smaller pieces. Amend each new hole with compost and peat moss.