Start by studying the tree. Don't cut it down if you see:

- Dead branches that are broken but attached, or that are actually broken off and supported by other branches. You're bound to knock a branch loose and have it fall on you.

- It is obviously leaning in one direction or heavily loaded with branches on one side. It will fall in the direction of the lean or load despite your best efforts.

- There are buildings, fences, power lines or other things you care about in the felling zone. If so, skip the felling and call a pro.