I believe that there are two methods of getting the data for range cards - actual shooting and computer generations from ballistic programs.
For hunting we keep it simple - usually use the excellent data cards from Ballisticards - they are comprehensive, heavily laminated and easy to use. Believe you can get more info from www.ballisticards.com
I also like the excellent little Pathfinder ballistic chart that you can attach to your scope tube - works like a little tape-measure spring loaded so ou pull it out and zips back into storage. Enough room on the tape for distances and drops. We covered them here in the past.
Another neat idea is to get some Avery labels, say 2"x4" and simply make distance and elevation charts, include wind drift info if you have it, and print the label yourself. We attach them to the side of our rifles, put Scotch tape over them to keep them waterproof. Some guys make up mini-sized labels and put them into the inside of the Butler Creek snap-up eyepiece cover.
What data? Distance and drop info in MOA is probably most important. We also draw a sketch of our mildot reticles and put drop info on it - what distance each dot is good for. I am pretty hopeless for numbers so I also put the basic .308 Winchester wind drift table for the 168 or 175 bullet that is standard - one minute less than the first number of the distance out to 800 etc. for a 10mph full value wind - also put the wind chart detailing field drift indicators for up to 12-15 mph winds.
All of this is available on the Ballisticard plus lead info for movers and other good stuff.
Good luck - we probably all do homemade charts differently, best to keep it simple. I have been out with guys who had slick print-outs for distance, wind, temps, barrometric pressure & elevation above sea-level, etc. The computer generated stuff is becoming very popular - get a good program EXBAL and you are in business.
Good luck, I am sure these guys will give you more solid info.