I used to be terrible about logistics. When I was first trying to make a living as a musician, I would constantly miss shows, misunderstand call times, and make other mistakes. I learned the hard way that you have to have a system, or things fall through the cracks. Here are the 10 steps that I go through every time I book a show now:
1. After I book it, I create an event in Apple's Calendar app and include the pay and the address, along with any other notes.
2. I add appropriate travel time before it.
3. If there's a contract, I attach a PDF copy of it to the event. It's easy to do in Apple's Calendar app- you just drag and drop the PDF over the top of the event.
4. I figure out due dates for the songs I'll be playing, and set alarms in Reminders.
5. I use my iPad for practicing, and I keep all my notes for practicing in the Notes app. I also use the ForScore app if I'm using sheet music, or need a metronome.
6. Two weeks from the event I follow up with my contact or venue. If there's a contract that hasn't been signed, I make sure it is. Again, my reminders app helps me not forget to follow up.
7. If there's a practice session beforehand, I take notes so I can focus on my weak spots at home practice time.
8. If it's an unfamiliar venue, I'll write down in the notes section of the calendar event the names of everyone I know at the venue. I add everyone I work with into my contacts app, along with keywords that help me keep track of everyone.
9. I try to always follow up with a thank you card after the show, and I use my reminders app to help me not forget. I keep a stack of stamped thank you cards by my desk at home, so I don't have to hunt for postage every time.
10. After the show, I write down notes of what I can improve so I can follow up on it during practice sessions. I occasionally use Evernote for this, but any note taking app would work.
Full disclosure: this is a fully fictional gig above, and while I have played for the amazing rooftop resturant Kemoll's in the past, none of the details in this event are accurate to what I actually made or did at the venue.