Well, I live in okla. I just hunted my first elk in NM lthis last OCT. I just did what the guide said. But I did learn a few things. Seems like elk hit water before they feed (early evening,late afternoon) and after they feed(early morning). So you can ambush them them at a waterhole. Also it is easier to call them in during the rut. In the rockys the rut is mid/late september so I would guess you missed the rut, even though it has only just gotten cold here.
Just about any cartridge that is over 140 grains will work, but the most popular seems to be the .300 win mag followed by the 7mm remington mag. 3006, .308, 270, and 280 rem are also good choices. I used a 280. Use heavey bullets (for .30 caliber cartridges, they reccomend a 180 grain bullet). Nosler partition is far and away the most popular bullet even though it is 50 years old!
Go to www.outdoorlife.com and search thier archive of articles for tactics and tips as well as bullet choices.
What rifle and caliber are you using?
okcmco