Some pics would be helpful. Advice for a freestanding rack will be (completely) different from a slide out rack. A rack with wheels will be similar to a free standing rack with one exception. You have to have slack to get the rack in and out in a roll out rack.

Freestanding Rack Tips

Racks should be planned during construction. You should know exactly where the rack will be before you pull a single wire. Plan the ceiling out so you have space (and access to the space) to hide a service loop. Service loops may never be used and may seem like a waste but in ten years or 2.. if the client decides to upgrade your cables will be long enough to reach anything in the rack. That means an old ethernet jack in the extra bedroom can now deliver video to a TV.

Avoid using Knock down racks like the slim5 if you can. These racks leave you ZERO space to manage cable. Same with the slide outs and slide out twisters. If you can get away with not using them.. DONT USE THEM! The best case scenario is a free standing rack thats positioned so you have the ability to walk behind them. These racks are super easy to work with and that means your guys wont get tired of straddling the slide out racks or fighting the cables in the twister racks and they will have plenty of space to manage cable up the back rails.

Plan for more rack space than you need. No matter what you do you will end up adding 5 to 10 rack spaces of gear at the end of the job. I cant tell you how many times i have seen AV Receivers sitting on their sides in closets or a stack of 4+ cable boxes sitting on one rack shelf because theres isnt room to use custom shelves.

Use custom length cables and dont leave unused cables hanging out in the rack or excess length along the sides. Custom length cables take longer and cost more but they leave zero mess and clutter. As long as your guys have connectors you wont ever run into a situation where your raping the directv boxes looking for component cables to finish up the install.

Use mini 23 guage coax for interconnects. Especially if your sending audio and video from the head end to the room end vs using baluns. The bulk of RG6 and even RG59 will fill your rack up very quick and make it impossible to manage.

Power strips. Make sure your guys have enough power strips/surge protectors UPS etc. This is often overlooked until the end of the job when you realize that every damn device in the rack has a walwart power supply that takes up three outlets instead of 1. I prefer horizontal power strips because they mount at the front of the rack and dont take up space along the back rails. Others prefer the vertical power strips because it puts an outlet behind each device. Choose your poison.

Schematics, rack drawings. Have the rack laid out before they begin and schematics for how everything wires up. Making decisions on where the AMP should go is easier to do sitting at a desk vs in a dimly lit basement with 20 guys trying to finish up work that the GC claimed was already done.

I literally had guys climbing thru my racks @ an install once. The contractors were supposed to schedule me when the basement was completed. When i got there i sat on my hands for 3 days while they finished the basement and painted and installed tile. When i finally started work i had 2 ganged racks that i had to swing out into the hall blocking the stairs. After the 5th time of rolling them out of the way i decided i wasnt going to move them anymore and they could climb in the window.. thats when they started trying to climb thru the rack. I mounted a couple of components to block access and played the @sshole all day telling them to go around. If that rack wasnt on paper it would have looked like hell because i was real tired of being there.

The less time your guys spend thinking about how something should be wired the better. The faster their job goes the more time they have to make it pretty.

Finally...
Try to eliminate types of wire you use. The racks im working on today have..

14/4
Cat5e
Cat6
Cresnet
RG6
23 guage mini coax

And thats it. We use Cat5 for everything we possibly can including IR and RS-232. Patching all of the cables in the house keeps the racks nice and tidy. The only cables that will be added are ones that are actually being used. All of the spare cables are not dangling down the rack.

Speaker cable goes straight to the amps. Done and out of the way. Cresnet goes to the C2N-HBLOCKS. Done and out of the way. Cat & RG6 go to patch panels across the back of the rack. Done out of the way. The 23 guage is used for interconnects. Cat5/RG6 and Cresnet are terminated right at the top of the rack so they don't interfere with anything else.

An example of terminating every cat5 in the house to patch panels.



An example of Cresnet being terminated at the top of the rack.



An example of taking speaker cable straight down to the amps and cutting it to length. Also see how using the mini coax for interconnects uses up less space across the lacer bars.



Even if the guys dont have time to make bundles perfectly neat they can still have a nice looking rack. Heres a pic of a rack i did 6 or so years ago. None of the bundles are particularly neat but because i have them seperated and following lines they look pretty good.