Some people practice making tunes as much as an other practices soloing. I'm the later - my tunes are developed by taking some chunk of a solo riff and putting song structure to it. Basically I solo all day and at some point whatever's new may or not become the basis for a new tune. .. When I say some people practice making tunes I'm thinking it's usually in drop D or complicated chord or power riffs designed specifically for a song. Finger picking maybe or chord voicings etc.