Running? Pfft... easy, here are some pointers:

Inside Runs:

Running inside is probably the least common seen by human players. They prefer running outside but I find it very easy to gain a few yards running inside (provided there is adequate blocking).

You can run between the center and guards, which doesn't require much skills (yet). The center pushs the Defensive tackle one way and your guard pushes the other tackle the other way to provide a gap to run through. The first step is to pass the defensive line. You shouldn't have to use stiff arms or jukes yet, but you might have to if nothing is open. Sometimes the gap opens between the guard and tackle and is very useful to sidestep to that hole (without losing speed). Once you have passed the Defensive linemen, your second step should be linebackers. Obviously, if you don't have a pulling linemen no one will be able to block the linebackers (especially in single sets in the backfield). That is where your fullback becomes useful. It is very important to look at him, this is mostly why people prefer to run outside then in (they can't wait for the play of develop). If your fullback hits the linebacker and his back faces the right side, run to the right side (follow his lead) he will push the linebacker to the left and if you are lucky prevent the other linebacker from getting to you. If the fullback hits the linebacker but his back is faced to the left, turn and sprint left. If he simply pancakes the defender, choose where you want to run. The third and last step are the defensive backs. From there you are 1 on 1 with them and this ussualy is where the good backs seperate from the average back. If you have a good back you should be able to spin (juke) or stiff arm the defender (depending on your backs strength) for a TD.

TIP: You need a lot of patience while running inside. Rookies (and pros alike) ussualy run to the outside because this is the easiest form to pick up yards. If you call an inside run, do not use the sprint button until you've passed the defensive linemen and make sure to follow your fullback or pulling guard. (Which is a good reason to have a quick guard and/or fullback) Let the play develop.

Outside Run:

This is even more easy. You should run lots of these with a fast runningbacks.

When running to the outside, you also should never use the sprint until you decide to turn the corner. Ussualy on outside runs the linemen all run towards the outside including your fullback. Once you see a cutback hole you may sprint which will break more tackles. If you see the cutback hole try to sprint and turn the corner. Once again, do not try to goto fast or this may result in negative yards.

TIP: You may also fool your opponent by running outside, but then stopping and throwing the ball to a wide open receiver. This is very useful with oponents who like to cheat the run.

REVERSES: A reverse is another form of running which is commonly forgotten. This play is by-far the least percentage of chance for you gaining positive yards.

Reverses are used for oponents who like to cheat the run and fool the defense. This play will either gain lots of yards or none at all. Use this with a quick receiver, but try not to use your primary receiver because the chances increase of him getting hurt. If you really want to gamble, try the reverse pass!

TIP: Never use a reverse unless you are inside your opponents 20 yard line.

Hope I helped, G'bye.
-The Milkman