Someone should have warned me that one of the most important things about being an author is having an efficient, extensive filing system. Not only do I have to keep track of what I named the girl next door who walks the dog in case I need her in the next book, I also need comprehensive lists of who showed up at my workshops and where they might want to hook me up with another engagement. Not only do I need elaborate timelines that include both real dates and the fictional events I've attached to them, I also need the names of every bookstore manager I've met along with his/her phone, fax, address, and, if I'm really good, the name of the second in command who helped me set up and probably will do the most to hand-sell books to customers. Not only do I need to remember pivotal plot events so that they can be cleverly worked into a satisfying conclusion, I also have to keep a file of people I've met at conferences and online: in which venue, who they are, and how we might help each other in the future. (This is particularly weird with online contacts, whom you may never meet in person but who can be vastly helpful to a career.) And not only do I have to keep track of books sold, given away, and consigned, I also have to know who I"ve submitted manuscripts to, how long its been since they received the material, and what they say about it when they eventually respond.
If I gave advice to aspiring writers (and I do, all the time), I'd say write down everything for the first year, organized or not, and then set up a system for tapping into all that knowledge. The method will vary according to individual tastes, and some will be better than others at putting information into usable forms. I think age has something to do with it; I used to be able to keep lots of different things in mind at once, but now it's safer to write it down. And it's really frustrating when I find a note in my own handwriting and think, "Now what does that mean?"
It's work to set up a system, and it's work to keep it current, which is the other bit of advice: pick a day each week to update. You can't set up an efficient system and then abandon it. Your Keep-Track files must be constantly updated, and if you get off the track, you have to work at it until you're back on.
Like I keep telling you, this writing thing is a lot of work. And a lot of fun.