Today I worked on (among other things) lat pulldowns. The greatest danger in doing this exercise is failing to keep your elbows in the line of the pull. Flaring your elbows out happens when you pull the bar to your neck and not your chest. You should always try to pull the bar to about shoulder height.
Keep your elbows slightly in front of you and then, in line with your hips, pull the bar down. You want to pull the weights using as little of your biceps as possible. Keep your focus on your lats and you'll quickly see a difference in how your lats are engaged.
Just another tiny step toward reaching my goal of climbing the Allalinhorn next summer. :-)