If I were in your position, I'd break down my goals for the practice week like this:
1. Know the names and how to play the basic chord shapes. Specifically, the open "cowboy" chord shapes as well as the basic 6th and 5th string root major and minor barre chords. Even more specifically, if someone says "play 4 measures of C major" you should immediately be able to associate that chord name with a shape and play that. 2. Focus on practicing the ability to keep a steady rhythm. Make sure you are able to play along with the tapping of your foot or a metronome without speeding up or slowing down, even if it means you miss a few notes here or there. It's not ideal to play a wrong note, but it is even worse to get off rhythm. I prefer practicing while tapping my foot, since if you are following the lead of a singer, you want to synchronize your rhythm with her tempo as you can hear it or even see it in the tapping of her foot or movement of her body, even if she seems to speed up or slow down at certain parts. 3. Have strum patterns for fast and slow songs. Since this is a crash course in rhythm guitar, try to become comfortable a strum pattern or 2 for both fast tempos and slow tempos, which will require different accompaniment. For example, fast songs may require a lively and strong strum pattern, whereas with slow songs may even allow you to use fingerpicking patterns. 4. Be able to read a chord chart and transpose. By chord chart, I mean lyrics with the chords notated above the words at which they change from one to the next. As for how to transpose...using a capo is easy and some people will call it lazy. But I could just as easily call using barre chords the "lazy and easy way out" if I were to let my jazz snobbery show...and I could easily suggest that you should be able to hear all the individual notes of a chord and how they each have their own melodic lines as you change from one chord to the next, and from all of that be able to construct a chord at any position on the next that naturally transitions from the previous chord in a pleasing way...while barre chords can get the job done but have sub-optimal voicings. In the long run, you do not want to have rely on either using a capo or even on using barre chords. But for now, since you have little time,just use whatever works.
And for the day of:
1. Accompany the singer. Don't think of it as Soviet Russia, where singer accompanies you. 2. Have fun. It'll be nerve wracking, but do your best to enjoy the moment. 3. Focus on making music. If you show up with the ulterior motive of making love instead, then you'll end up forever alone and without people to play music with.
The first one said straight up that I didn't cut it. Though I appreciate the honesty, it stung a little. The second one wasn't even a singer and just wanted to bang a guitar player. The third one didn't show up.
Guess the fourth one was alright, we played a little and she had some cool ideas about songs we could practice, let's see where this goes.
I suppose the overall experience seems, as you put it, sobering. Sorry to hear that. Did the first singer at least explain why she thought your current level of skill isn't up to par? While it is hard to hear that kind of feedback, you can make it more of a positive overall by using it as a learning opportunity.
On the other hand, taking the fourth case on its own, it sounds quite promising. GLHF.
She said my rhythm was really great (probably to blunt the impact of what comes next), but I have no idea which chords to string together. No argument there, I'm in in the process of learning that. Basically, she had hoped I was a lot more experienced, though I made my level of expertise pretty clear beforehand.
No crying over spilt milk, though. I have loads of stuff to learn and the pressure is gone to do it within a week's time.
By the way, I largely used your crash course to prepare, and by the fourth time, I absolutely killed it with a semi-improvised piece of finger-picking. Still suck balls at strumming, though.
Elliot Smith is a guitarist I really admire and he has some cool finger style strumming technique he uses a lot.
You might want to look into that kind of stuff if you are against playing with a pick. I like playing with picks so thats what I use, you can find a way to make what you want work though ^_^
Personally, I would prefer to be told that I have great rhythm but also that I still need to work on learning chord progressions, etc. The importance of rhythm cannot be understated. When performing live, I would much rather hit a wrong note here or there but stay on the beat, than play all the right notes but without impeccable timing. The other people in an ensemble and even the audience generally share that sentiment as well.
As for whether or not you need to use a pick, I would say that there are plenty of techniques to explore before you should feel that you need to do so. Andy McKee and Preston Reed for example, generally strum downward with the 4 fingers and upward with the thumb but sometimes strum with just the thumb, etc. Adapting some fundamentals of flamenco strumming could also prove helpful. And there is always the thumb-pick.
What type of music is your goal? I can make more specific, i.e., more meaningful, recommendations based on that.