Here's what a typical hand setting tool looks like:
http://www.hollanders.com/supplies/V...4-5cd139b88816
The setting tool or squeezer head must have the dimple in it for tubular rivets or they will just crush instead of rolling over as you set them.
You want to back the flat side of the rivet up with a concave tool so you don't flatten the head as you set it. Sometimes a piece of hardwood like oak can be used as it will give just enough to conform to the head without flattening it.
Darryl