Just a few thoughts, as a grad student who did not finish her degree:
Feed back is extremely important. Talk to your students on a regular
basis. Whether this is formal or informal would depend both on the
students and on the professor. But above all, talk to them!!
Be aware that there may be external factors affecting your students'
performances. These problems may be out of your realm of expertise; if
so, refer the student to a counselor who can help. Depression is quite
prevalent among college students, and grad students are not exempt. And
any problem can be solved in one way or another....
As far as firing a graduate student...if they are totally non-productive,
then you may have no other option. My professor hand-held one student, to
the extent of detailing her research for the week, but she ended up
quiting anyway. Would have been easier to fire her. But if a student is
in the throes of writing a thesis, cutting off the money can be
disastrous. The thesis may never be finished.
