Checking Trans Fluid level

Is there a decent way to check the fluid level in the transmission? My first thought was that it had been low for a long time so I put a quart of the most expensive stuff I could find from AutoZone (Valvoline MaxLife) and I noticed that the 2-3 shift is a lot better (much less lag and crisper). But anyway it doesn't matter whether the car is warm or cold; whenever I put the dipstick in and bring it back up there are "dry spots" below the low marks, but trans fluid still goes up to about four inches above the end of the stick. How can I get an accurate reading?