In early spring, it's best to put down a layer of leaf mould or compost to prevent the grass from dying. If you want to plant something in your garden, now is the time for that too.
It's important to plant flowers that are going to flower quickly. That way you don't have to worry about dead plants later on. Some good flower choices include tulips and daffodils.
One thing you might want to consider putting on your lawn is a tree so that the yard has some shade during the day time while still getting the benefits of having a tree in front of your house like beautiful flowers and fruits.