Watch the Mixolydian Licks - Part 2 online guitar lesson by Jeff Scheetz from Blues Jam Survival Guide
One way to be more melodic is to pay special attention to the root notes and you are soloing. I try to get all beginner soloists thinking this way because it makes even someone who may not have killer chops sound pretty good pretty fast. So be aware of where the root note of each chord is, and then after you do a lick in the scale, get back to the root of the next chord. This also keeps you from "meandering" through the scale and gives you a place to go "home" to.