I had to fly in ATTI the other day to shoot a house surrounded by trees and it was NOT a fun flight. The house was near the ocean and it was breezy that day. It gets exciting when you get to an altitude and spot where the wind is not blocked by the trees. All it takes is a little bit of wind and it really drifts in ATTI mode.
Here are some tips that may help:
1. Hold the sticks near the base with your thumb and forefinger so it's easier to make small, corrective movements to the flight.
2. You fly the bird and have someone else holding your phone/tablet and taking the pictures.
3. Be patient, especially if it starts to drift. You focus on the flight while the other person worries if they got the shot or not.
4. Take lots of pictures. If you are having a hard time controlling in in ATTI mode with the wind making it drift don't expect to take one or two shots and get the perfect photo.
5. ALTITUDE IS YOUR FRIEND. Try and set the shot in an area where you can gain altitude above the trees if things start to get hairy.
If at all possible, set your home point in a clearing away from where you are flying and at an altitude above the highest object between where you are shooting and the home point. Hopefully if things go bad you can climb above the trees and RTH to regroup and start again. Whether or not you set your home point away from the target pick out a safe landing spot before you fly. Where I was shooting I saw that if I needed to I could climb out above the trees over the house, hover, then walk out back and land on the golf course.