Make sure you are using the entire stereo spectrum on your mix. Then - buy iZotope Ozone 9. You don't need the pro version - which is pricey (unless you can afford it). You can get the "elements" version for around $120. Game changing mastering software. WAVES is also great for the price. They both do things to your mix that you simply can't do in a home studio.
Download the 10 day trial and try it on a couple of your mixes. I think you'll really love it!