Michael, I just took a look at it. I'd like to focus on the harmony. There are several places where melody notes clash with the chords in a way that does not have a blues sound. For example, in the second measure the melody has a Bb (natural 4th) and an E natural (major seven) on an F7. In a similar way, the second measure of the third ending has an F with a fermata on a C7. There are other examples throughout the tune. Do those notes sound right to you or are they typos?
Also, check the 3rd measure. The C 8th note on the first beat appears to be a typo...in particular, since the triplet following it starts on the up-beat. I'd think that C should be a quarter note.
A blues scale that I often use on dominant 7th chords in a blues setting is 1, b9, #9, 3, #11, 5, 13, b7. On a C7 that would be C, Db, D#, E, F#, G, A, Bb. See how these notes sound to your ear played against a C7. In particular, compare using F# to F natural on a C7. This scale can then be transposed for other chords.
Please understand that I am not a purist about vertical harmony. When the musical context feels right I like to stretch and go beyond conventional harmony in various ways. One of my role models is Lester Young in how he sometimes used "wrong" notes on chords. While they were unconventional in terms of vertical harmony, those notes worked beautifully in an extended linear way in the melody. That is, they expressed a broader blues tonality. Whereas, the particular unconventional notes you're using do not have the same effect. For me, they simply sound like wrong notes.
Do you play some amount of piano? If not, it is important to do so in order to hear how the melody notes are working with your chord changes. I don't have much piano chops. But, even the sorry piano playing I can do is extremely helpful to me as a writer.
Hope this helps.
Roger
