Originally Posted by: light487I've only been in a recording studio once.. but I'd say the biggest thing is to have everything worked out down to the last decimal place. Particularly things that would otherwise be done as improvisation when playing live, such as the guitar solos and other instruments' solos.

This is for the most part true, but the part about solos is more of an opinion. I find it best when soloing to have a few main points to the solo but then improvise the stuff in between. Then do a few takes of it to see which on you think turned out/fits the song best.