Use the range and speed on your normals, or some cases specials, to cover all the space infront of you, making sure that you know what moves are gonna hit or miss your opponent. Also knowing your opponents range and speeds will help you determine when its safe to dash in and punish a slow normal or special.
Knowing the frame advantage or recovery on moves will assist you in knowing what you can do to keep your opponents at desired ranges, where you have the threat of a combo stopping them advancing that tiny bit extra to hit with their tiny t rex like normals, or go to the air , anything that you can punish really. Its all based on reads and reactions to certain things, you cant really format "footsies" like you would a combo or frame data because theres no real measurement for range in mortal kombat, i know in sf4 theres squares on the floor in the training room that some people would use for showing range and footsie, so osmeone could try if they were that interested.
You should just get the feel for your characters normals through use , and know about matchups to play good footsies, but its played in all levels of the game, everyones got pissed at milenas d4, thats just footsies for ya, very easy to apply with good normals though.