If you're doing a job for the first time, remove bolts/etc & lay them out as they came off (sometimes bolts are a different length) & then when you've removed it thread the bolts where they came from in a couple of turns.

Digi cameras are great for this kind of thing, especially if you won't be putting it back together for a little while. 
Agree here

Also mark all cables both ends, and take a pic of how,where they come from, might seem obvious when you take them off,but are they going back straight away? more than likely not, I do this all the time and belive me, even when you think you remember, you don't always,especially the next day 15 jobs later, 1 wrong cable/ lead and it can turn into a nightmare. It takes a few more min's to mark things but goes back a hell of a lot quicker,when its marked you say to yourself, "oh yeah I remember that came from there," but trust me, when its not..... Im sure that was there...

Moving on...the digi camera or I use my phone to take pics of things as they come off, part numbers too. Added bonus, you can send to ya m8's, post on the forum etc. takes an extra 10 secs to take a pic'

Another tip, if your phones got the facing camera, ie video calls etc, if you cant see an item, often you can put the front camera on, point it at the thing out of view, you can see it it the screen, then take a pic, I used this method when I couldnt see the tool needed to take off a bolt from behind the brake shield, couldn't determine if an Allan bolt or torque,worked a treat with a clear pic', but I use it all the time as memory so bad

I think the best advice is, don't rush, take your time and do it properly,in the end its quicker.
Good Luck
