For someone who's starting off as you are this will take you much time, practice, trial&error... and forum searches to get what you want - unless you're simply attempting to put together a c-grade demo for a rough idea. You have a sound in your head and you want to hear it through your monitors right... that won't happen overnight. Stick to it, its ok to be over critical of your work right now, if you're serious about it you don't want to settle for a mediocre/passable sound. Keep playing around with certain elements in your mix process. But know that no amount of mixing will make a shitty dull valvestate gtr tone into a bright/vibrant warm tube tone. Gotta start with a great sound... if you have a great sound already coming into a mic there's way to make it more brilliant, if you have a crappy tone going into a mic mixing it will be like polishing a turd... its gonna be crap no matter what you do. You'll eventually develop an ear for these things and when it comes to mixing guitars less is more and more is less in most cases.