On #2, I've seen it claimed -- but have no idea how good the science behind it is -- that better than visualizing positive or negative outcomes alone is doing both and paying attention to the contrast. "If I do X, then the result will look like Y. If I don't do X, the result will look like Z. Wow, Y is much better than Z: better get on with doing X".
The keyword for that research is mental contrasting. It was previously discussed on LW here.
My impression is that the quality of the science is relatively good, compared to other psychology research that was done in 2000-2012. But as far as I know it has not yet been tested with the improved research methods that have come out of the replication crisis (e.g., I don't know of any large sample size, preregistered studies of mental contrasting).
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