We've all pretty much said the same thing each time.
My direct advice to you would be to read what you can on the subject whilst you're not practicing your guitar. When you then sit down with your guitar play what you've read through and listen to the sounds you create. You only need to do that for about an hour whilst you play.
Once you've done that you then play whatever the hell you wanna play. Excersises, whatever. It's just something to help you with sounds.
When you write a song you should than know the sounds of each scale and be able to match solos up after youve written the riffs.
I didnt explain that very well, Im in a rush. If you want me to explain better just pm me or something.