I also teach the thumb method.
1. Get your clearance.
ex. "Hold NW on the 305 degree radial, left turns, expect further clearance in 20 minutes."
2. Determine Outbound Heading. I think the easiest way to do this is to look at the holding clearance. If the direction of the hold, "NW," is close in line with the holding radial, "305," then the 305 will be the outbound. As in, 305 degrees is a NW heading, therefore it's the outbound. Use that Holding Quiz crycadian provided to practice this as well. (Thanks BTW, I have that bookmarked now).
3. On the DG, place your left thumb on the left side for left turns or place your right thumb on the right side for right turns. This allows you to divide the DG (or HSI) into sections. There will be a line drawn from the top of your thumb through the airplane in the center (So it will be slanted) [See Picture]. The "Teardrop" section will always be next to your Thumb. Think T for Teardrop, T for Thumb. Also, this is assuming you are going direct to the fix at this point.
4. Find Outbound Heading and determine which section it is in, that'll be your entry.
Then you can figure out what you'll do next upon reaching the holding fix as far as the entry procedure is concerned.
Direct - Turn to the Outbound heading.
For Parallel and Teardrop, think POTS for what direction of turn you'll do after one minute past the fix, Parallel Opposite, Teardrop Same. For Parallel, turn opposite the holding turns. In this case, we are left turns so after one minute on a parallel entry, turn right to intercept.
Parallel - Fly outbound on the holding course for one minute, then turn towards the holding side to intercept the holding course to the fix (I use a 45-degree intercept).
Teardrop - Fly outbound on a heading that is 30 degrees towards the holding side then turn to intercept the radial course to the fix. POTS, teardrop same, so the turn to intercept is the same as the turns in the hold, this case, left. Also, the whole 30 degree heading can be confusing, but you can use TLARS to help calculate that heading. Teardrop - Left Add, Right Subtract. If the turn in the hold is left, add 30 degrees to the outbound heading. If the turns are right, subtract 30 degrees from the outbound heading. This will be the heading to fly for one minute. Hence why finding the outbound heading is so important.
Also, this is all assuming 1 minute legs.
Hope this helps, and remember, flying instruments is fun, so make it fun. Good Luck!
EDIT: Can we attach photos on here? I can't seem to find an attatchment thingy.