A lot of this is a training issue.. I know that sucks to hear, but it is.
In real world environments a lot of masking occurs and sometimes targets don't just jump out at you because their temperature is nomilized with their environment.
Using Mark points, talk ons, HMCS, Wild Weasel in some cases, switching color spectrums, and grid searching are the only true ways to draw out a target.
Sorry for the frustration. If you ever feel you need help training any drills to help with what I just stated, let me know..
