Step one:
Any old piece of sprue will work. Only ensure it is long enough to heat up without burning your fingers. When I am heating sprue, I roll it in my fingers over the flame to ensure the piece gets even heat.
When the sprue is beginning to droop is the time to stretch it out. NOT TOO MUCH! Only stretch it about a centimeter and then bend it down to make your hook. This is an example of the shape you are going for:
Trim off the excess leaving yourself enough room to shape your point on the hook. I always leave the other side of the hook attached to the sprue for a handle while I work...
Using an emory board (or a jeweler's file) I begin shaping the tip. No need to hurry here, just work slowly stopping often to verify you are getting the shape that you want.
Once you have the tip where you want it then you can start thinning down the back side of the hook. I generally use a Dremel here with a cylinder cutting bit to remove the large rough areas. After you have gotten the shape you are after on the backside, use the emory board (or sandpaper; your preferrence) again to smooth and detail the shape.
Of course you do not have to use my cut line. This hook is for a BMP and will attach to the vehicle itself, not a chain. Remember, you can also cut/drill any holes you need in your hook now if you are attaching it to a chain or rope/cable.
Finished and attached tow hook.
Not really much of an article, but the technique is cheap, easy, and in my opinion, very effective looking in 1:35 scale.
Happy modeling !