These are some things that I've picked up from my influences over the years and may help your playing.
"When we heard this, we were really stoked. It made us want to grab a guitar and play along. If that isn't musical success, what is?"
Fingers and Thumbs: Using your thumb can get your a real full mellow tone a la Mark Knopfler. Your fingers can get you a great snap if you dig under the top strings - a favourite of SRV.
Pick Palming: Playing fingerstyle can really add some colour to your sound, practice being able to palm your pick so that you can use your fingers and then go back to the pick again.
Picking Variation: Try different ways of holding the pick to get variations in tone, holding the pick tightly between thumb and 1st finger gives a thicker sound, more loosely between thumb and 1st and second fingers a lighter sound. As well as pick holds, playing in different areas (neck mellow, bridge crunch).
Play Along: Put on your favourite albums and just play along, dont try and pick anything up directly just improvise along with the tracks and get the feel of them.
Distortion and Rhythm: When recording rhythm guitars, keep the distortion level down, this will keep it clearer and tighter in the mix.
Listen Low: When mixing a track, set the volume right down low (or step out of room and listen through the open doorway). This is a good way to see if you have got all the instruments balanced, make a point of listening for each instrument.
Allow Ideas to Develop: Sometimes I have a desire to lever a song in the way I want it - but it works far better when it is allowed to develop in it's own way, even if that is different to what was expected.
If it Sticks: If you have an idea for a riff, play around with it for a day or so and then leave it for a few weeks, if it still sticks then that's a good sign it's half decent - this one is a dangerous tip of course if happen to forget an absolute killer! I still record all my ideas first up as well for safety.
Record Yourself: The best way to learn about writing is to write stuff and record it, then listen back and be your own critic - hearing yourself is a great education for playing and writing.
Gear n Tone: Every part of the gear chain from the guitar strings to the speaker affects your tone, changing any part can improve it so have fun and experiment.
Tweak Your Kit: If an amp or effects pedal isn't doing quite what you want, search the web to see if anyone does mods for them that might get you where you want to be - you can of course mod yourself if you are confident with a soldering iron.