Practice practice practice. And patience.
A methodical and logical approach to searching for your targets is the best way to find them.
My method:
1. Approach the target area
2. At around 7nm from target area, put the area on your 90 and start a very gradual clockwise turn. Engage altitude hold autopilot.
3. Use TGP to scan for targets in the expect area. Be careful not to wander into threats.
4. Rinse, repeat.