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A look at "Give Me One Reason" by Tracy Chapman, which is a brilliant 12-bar blues to put together once you've got bar chords under your fingers. You could capo it on the second fret and play it as E, A and B, but Tracy keeps it in F# and makes a real feature of the open strings, so I'd start there.
The first thing to nail is the groove — that percussive tap on beats 2 and 4, sitting alongside the root notes. If you're someone who has to count everything out loud to play a song, this is a good one to break that habit on. Counting works while you're learning a song, but the moment you're trying to play something at this level you need to feel it rather than say "one e and a two e and a" in your head. Put the count in your foot if you have to, but get it out of your mouth.
From there it's a standard 12-bar blues structure — the first four bars sit on the F#, then the move to the four chord, with that little riff up to the five chord, and on bars 9 to 12 you get the five chord, four chord, one. The strumming is roughly down, down, up, up, down, but with mutes built in, and a few of those downs land on just the root note or a power chord rather than the full shape. I get pretty loose with which strings I catch — plenty of ups to make sure I'm hitting the thinner strings.
The detail that really makes this record is the single-note opening on the open string and then the second fret, plus a relaxation of the bar chord on the strum that causes the mute. A more beginner attempt with everything ringing out cleanly is fine — it's a level most people have to reach first — but it won't have the vibe of the record. The mute comes from the fretting hand, not the strumming hand, and Tracy's bar chords are the kind that sit nicely on a radiused fretboard like a Strat. They're much harder on something flat like a Les Paul.
The lead line at the end has a lot in common with the Clapton player study from the beginner electric lead course — all of that would work over this song, you'd just need to shift it from A to F#.