Write more.
Yeah, I've found this is key. I've known a lot of really skilled guitarists that fall into a trap of writing really intricate stuff that never allows itself to become a simple expression of the person's feelings, thoughts, desires, etc. I would suggest just writing and recording a few songs on your computer, waiting a few days, weeks, then listen again and take what you still like and make it better, if that's even necessary. Either way, whether you're improving on an already existing song or writing new material, just write and record some more stuff. The most important thing is to finish something. Allow yourself to go through the entire process of writing, recording, and being done with it. Soon after doing this a lot you might start to find yourself writing and recording stuff you really envisioned yourself writing from the beginning. I noticed a long time ago when I used to listen to the electronic group Boards of Canada that they have like 5+ versions of individual songs sometimes in various levels of completion, which meant it probably took them since the original version of the song, almost 10 years in some cases, to perfect it for the full length album. Approaching writing music like this, by just going through the entire writing and recording process over and over again until it feels like something is really finished, might help you.