I put all my effort into the show itself.
First I try to find out what I can about the venue if I've never been there. TS is a great place to find out what the venue attitude towards tapers is, how the acoustics are, best spots to set up, etc.
Then I do whatever I can with the logistics of getting in and setting up, while trying to find a balance between respecting the venue and pulling the best tape I can. I always have a tapers ticket if there is a section, but a lotta times I will buy a second ticket to see if it is cool to tape from a better spot than the section if there is one. Some venues are totally cool with taping from your seat. If not, I respect the venue's wishes and go to the section wherever it is.
Once I am set up. I just roll it and enjoy the show. Sometimes I'm really excited about the results. Sometimes I'm really disappointed. Most times I am reasonably happy. Almost always I feel like either a recording does not need any real post, or in the worst case, probably cannot be improved much by any post.
Granted, I don't really know anything about post production techniques. But my gut feeling is that I have the sound mix of the show, the venue ambient acoustics at whatever location I end up, the crowd noise, my mic characteristics and whatever color or lack of that my gear's analog stages add, all rolled into what at the end of the night is a lot of complex factors combined into only two (or for a few four) channels of a complex sum of the information from all these many sources.
Sure you can tweak the sound some post. But how much can you realistically do with what you end up with? I really don't know. I just do whatever I can going into a show, then roll tape and have a great time with it all...