I've tried going through a variety of tutorials, and have seen a variety of techniques for knocking out people from backgrounds in Photoshop...but none seem to show how to properly clip hair if the person is on a busy background - they're usually all on solid fills. Can someone offer a step-by-step process for properly knocking out an image of a person (with blonde hair, preferably) on a busy background? Thank you!
Knocking out a very busy background is tricky, any of the built in tools probably can't do the job.
In these situations I usually clip as close as possible with the pen tool on a new layer. Then use a very very thin brush on a new layer behind the clipped image to draw in the tiny hairs that you can't get in the selection. A 1-2px brush with a fade control in the shape dynamics works well. I usually set it to 2 steps and a minimum diameter of about 20%.
You're essentially drawing it in one hair at a time so I recommend a Wacom/pen tablet of some sort.