Thanks again. For various reasons, I'm simply not able to have a 'proper' monitor set-up (space, cost, and most importantly time - I cannot mix 'out loud'). So, I simply have to work around the limitations the best I can.
-- baltergeist
As far as plug-ins, FabFilter makes some of the best plug-ins in VST format. So if you can afford to get the bigger bundles, you should be good as far as EQ, saturation, compression, limiting, reverb, etc. I'm assuming that you also have a decent audio interface?
If you have to mix on headphones... then reference other professional work that is similar to your own for balance. Also playing things back in the car will also help if you spend a lot of time listening there. You'll spend a lot of time going back and fixing your mixes at first until you develop an ear for what a good mix sounds like in your headphones.
Mixing in headphones is far from ideal. But it can be done if you have to. Just keep making music and doing what you do.