1. Do not accept offers of non-matriculation, unless that's the route you want to go, are taking courses for personal interest, or just trying to boost your record without having that school as your top choice. I was burned very badly by a school in which I went non-matriculated, took graduate level classes, received very high grades and was told by professors and the DGS that I would be accepted, and was rejected without mercy. I would have saved myself time, money, and heartache had I just applied to be matriculated.
2. Cast a wide net, and look for creative ways to market yourself. After doing years of work in my field it dawned on me that I was a perfect fit for programs focusing on applied forms of study rather than traditional academic work. This application season marketing myself this way got me in.
3. GPA and GRE can only hurt you, not help you. What makes your application stand out is your SOP, LOR, and CV. I know quite a few precocious freshly graduated colleagues that figured they were in everywhere based off of their 3.8's and 1400s, which did not end great for them!
4. Persistence and patience pay off.