Avoid using duct tape or plain masking tape unless you have no choice in the matter. I have seen pro engineers using (good quality) electrical tape, or gaff-tape on their consoles, and these are fine, however, I personally don't like either(not pen friendly).
Artist's tape is kind of a glossy surfaced paper tape that resembles masking tape; it was once common, but lately, I've been having trouble finding it. The name brands offer their own specialized "board tape" or "console tape", but this is just artist's tape re-branded and sold at an inflated price.
Whenever I mix, I use white artist's tape and multicolored felt tip sharpie pens. Then, once everything's labeled properly, I apply clear scotch tape over top of this to prevent smearing. If I need to, I can still write on top of the scotch layer, then apply yet another layer of scotch over this (sometimes up to 6 layers)!
I sometimes apply 1 or 2 additional strips of blank white tape with a few layers of scotch just below the channel labels, and use this as a sort of scribble area for on-the-fly notes and such. Just peel off one of the scotch layers and you have a clean strip!
And as a habit, I try never to leave tape on a console unless I must, (even then I try to replace it every few days or so). And I would never......ever use those electronic label maker things on any console, as they are often a pain to remove.
Here is a handy hint:
Create for yourself a kind of "flight bag" that contains all your basic tools like board tape and markers. Include stuff like:
1-roll of black gaff tape
1-roll of yellow gaff tape
1-roll of scotch tape
1-roll of black electrical tape
rolls of colored e-tape
2 or 3 good pens
1-pad of stick-notes
3 or 4 sheets of scrap paper
1- small clipboard
some blank generic pre printed patch spread-sheets
1- virgin paint brush ( for sweeping dust off the console)
1- virgin makeup brush ( for getting in between knobs and stuff)
1- mini screwdriver set (need I say more)
1- medium sized adjustable c-wrench
1- small pair of needle nose pliers
1- small pair of wire cutters
lots of zip strips
lots of velcro strips
1- cigarette lighter and some shrink tubing
1- small pack of band aids.
hand sanitizer
2- good flashlights
8- fresh 9v batteries
10- fresh AAs and AAAs
1- pair of decent walkie-talkies (just in case)
1- jack knife or similar multi tool.
YOUR SPARE PHONE CHARGER!!!
1- spare USB drive
1- spare USB cable
1- spare cat-5 crossover cable
1- short extension cord with multiple outs
Your SPL meter
Your XLR tester/Q-box
Your AC outlet tester
1- spare direct box
1- spare SM58
2- spare XLR cables
1- spare 1/4 TRS cable
2- ipod-to-stereo XLR cables
1- pair of small binoculars
1- old pill bottle (gaff it to the side of the console and put your pens and stuff in it!)
1- generic All Access lanyard (just in case)
2- small clean hand towels
1- old rag
2- small bottles of water
sunblock, sunglasses, and ball cap (for outdoor work)
1- spare t-shirt (hey ya never Know!)
chewing gum, candy, energy bars, advill, etc.
I take a bag like this with me wherever I mix; It's saved my rear many a time! 
Exactly what size should the small clipboard be?
