I maintain two separate documents -- a trade LOG in excel. It has columns labeled "date" "description" "$" and comments
The description is just something like "Buy 10 65/65 TIF @ 3.00"
The comments section MUST be short. On earnings trades it'll say "BE $3.03, close by EOD Tues 11/28)." On my DD, it says "max return of 4.5% on $5,000.00" or something like that. (date and money should be self explanatory). The comment section always has my closing price, closing date, and things to watch for.
I then maintain a trade diary, which is a word file, where when trades go bad, or go well, or I start researching a new one, I take notes. It's quite extensive, and I update the index about every two months or so (word will prepare an index for you). I index by types of trades (e.g. earnings, DD, calendar, IC, RIC, etc), as well as symbols (e.g. AAPL).
I also have a notepad that I work out P/L graphs and sometimes backtesting as well. I have a big file for those, I date them, and then reference them in the trade journal. For instance, when I was backtesting the XOM DD, I used about 4 sheets of legal size paper. When done, I dated them, and then in my trade journal, typed the conclusions and noted that I had backtest on my notepad and the date (in the trade journal, I note that as "NBP 11/11/12" (NBP stands for "note book paper"). If I ever go back to my backtesting process, then I just find the entry in my trade journal, and go pull the results. That's pretty rare -- I'm normally only interested in the conclusions, which I transfer to the journal.
I update my trade log in excel as trades get filled -- I find if I don't then I find I get behind. I also have it up all day. (I highlight active earnings trades in yellow, DD in orange, cc in green, etc.). When a trade gets closed, I just take the highlighting off. This gives me a quick reference to look at regularly (as in multiple times a day).
I TRY to update my trade journal/diary daily. That doesn't really happen. I frequently have to go back and fill it in on the weekends -- but I do always at least make an entry if I need to put something in it (so for instance, today's entry might just be "11/26 - enter BT data from IWM" and this weekend I clean it up.
I file my notes from the pad about twice a month.
Yes this is a ton of work -- but trading is a job, and if you don't treat it that way, it's very hard to succeed.