The oft-repeated maxim that there is never a second chance to make a great first impression is especially true when it comes to real estate. Street appeal may focus on a dramatic approach to the front door, but prospective buyers will be especially "wowed" by an appealing back yard. Early spring is the perfect time to add some new plants, set out pots of blooming flowers and focus on one memorable feature. A little work now will pay big dividends later, in terms of buyer interest, increased showings, quick offers, and even a higher price. Here are 7 ideas that are…