Conditioning/training value of objects in experiment In visual attention and decision making, how do experiments teach participants the value of specific objects (high vs low vs none)? 

Does anyone know of studies that done this which go into reproducible levels of detail about their procedure/paradigm?
Subjective value is most often manipulated using some sort of incentive structure in attentional studies. Most commonly, the reward is in the form of time or money earned either directly or through 'points.' This is a very simple and common thing to do, so I don't know what you mean by "reproducible details" -- most studies will report little more than having creating experimental conditions along these lines, because that is sufficient. I will try to give a more detailed example, however.

In an unpublished study of eye movements and attentional capacity during a visual memory task, we would manipulate the weights of certain shapes by rewarding the participants with different amounts of points for different shapes. Thus, in one condition, circles would award 90 points, while triangles would award 10 points. Participants were taught this through audio feedback, and were aware that they had to accumulate a certain amount of points to complete the experiment. (The study was not published because a subtle critical error in the experiment code was discovered near the end of data collection.)