Weak in the Knees Serena Rider Capo 5th Intro: C Am x3 Verse: First, I play this with a capo in the second fret, just to get the vocals up an octave works well for me. As for the riffy things, all I do is add a little run down from C to when playing the chorus. So that would be C, C add2/B, Am. I also throw in a couple of "double fingering" techniques, such as in transitioning from the G to the C you can off/hammer on with your index finger on the 5th string, second fret just be (azchords.com)