What do I need to do to ensure I don't kill myself with a finger of death (or wand of death)?

I'd like to still make the most effective use of finger of death that I can, of course.

Spoilers I've read have been somewhat unclear - if I have magic resistance and reflection will my own reflected finger of death rays kill me?

If so (or, for a character that doesn't have them), what do I need to do? I don't think a bank shot is safe, since those (rarely) rebound and hit the caster. As far as I know I would have to be certain of a clear shot, and the target would have to be more than 1/2 of the ray's maximum range (in case the target has reflection). And I would have to be sure there is no creature I can't see in between us, or at least no chance of any creature that might possibly have reflection.

Magic Resistance and Reflection both render Finger of Death safe to cast, either via wand or spell, in most situations. Nothing will prevent suicide via targeting yourself.

There is a 1/20 chance of a reflection bouncing back at you, so you do need to be certain of a clear shot. A good way of checking if a shot is clear of invisible creatures is to throw an object, such as handy daggers, first. There are far fewer monsters with reflection than magic resistance however, so that won't often become an issue, especially since you're more likely to find reflection or mr than a wand of death.