You might try upgrading your soundcard first.
Your left/right balance problems could be either that you are recording stereo track from the keyboard and they are mixed within the keyboard with that imbalance, or that your soundcards inputs and not matched very well.
I am not a Cakewalk user, but I will make an assumption that Hi and Lo ARE your eq's, albiet, very limited eq's. You can insert a directX plugin over the tracks, but it would be better if you actually record a track that sounds the way you would want it to sound. Aux 1 and Aux 2 are Auxillary Sends. You can use these to send several tracks of audio to say a reverb plug in and adjust seperately how much reverb each track will get.
Blade Encoder is not considered to be a very good mp3 encoder at 128kbs (it's default compression setting). I use Audio Production Studio with a Fraunhofer codec. Blade will work just fine if you can get it to encode at 192kbs or higher, but, your mp3's will be quite a bit bigger too. Also, Blade uses a command line interface to change it's settings, and I have found that it doesn't always work when you try to change it.
If you think you are going to get great results from recording in the manner that you do, and I mean results that compare favorably to professionally produced CD's, well, your chances are very slim indeed. In addition, you don't seem to have that much experience in recording, thus, you should approach what you are doing right now as part of a learning curve. It is quite possible that the recordings you are comparing yours to enjoyed MUCH better equipment to record with, and engineers with YEARS of experience, and a producer that knew how to get everything jiving. Most of your questions so far have been very broad in nature or showed a lack of knowledge in basic stuff about recording. You might gain more by taking things a step at a time like inquiring in the Cakewalk forum we have heard about how to USE the features in the mixer section of Cakewalk.
http://www.homerecording.com , this sites main page has some more of the basics about recording. Feel free to check it out.
Good luck.
Ed