"electric guitar panned hard left and right"
You almost never want to pan anything
hard left / right. It creates ear fatigue for the listener very quickly and just plain sounds odd. Also, instead of thickening a mix (which is what doubling is usually meant to do), it does the opposite and thins it out. The warmth of the lower mids just seems to disappear along with the heart and soul of the music.
A couple of tips:
1) Get a good mono mix first. If you can't get it to sound good in mono, it will never sound good in stereo.
2) Respect the old adage: "The best EQ is no EQ." Obviously you'll need to EQ things from time to time, but it's far better to track things as well as you can in the first place. Use good headphones while tracking, and if the instrument(s) you're recording sounds like it needs some EQ'ing no matter what mic you use, it usually sounds better to do it at the mixing desk going in than it does using an EQ plug-in after the fact in my experience.
3) Watch how you apply
stereo effects. I think a lot of people using a DAW will track everything in stereo even if it's a mono instrument (meaning each side of the stereo waveform has the exact same thing on it). Some stereo effects are meant to take a mono wave and give it a pseudo stereo sound. This often gets lost when applying it to a stereo waveform that has duplicate waveforms on each side, so instead you get a mono sound for the most part. You have to experiment with effects to see how they react to various kinds of mono vs stereo waveforms. I think tracking in mono is usually the best way to go when using mono instruments and vocals.
You should work on things so you can learn to do it yourself. Mixing and mastering is not difficult. You can do it!