I know tons of tricks on Reaper, but I wouldn´t know which one is obvious.
Anyway, one thing that helps me a lot is to create buttons on the MIDI editor to set the selected notes to custom velocity values. This way I can make a button for each intensity of my drum sampler. It becomes easy to choose how hard I want each hit to be without having to guess or memorize the velocity range/region that triggers each sample intensity.
While there are no actions that allows you to set the an exact velocity value, there are actions to 'add 1', 'add 10', 'remove 1' and 'remove 10' from the velocity. So I create a new action where I stack 13 "remove 10" actions (the max velocity is 127, so stacking 13 'remove 10' actions assures me that the value goes to 0) and then add as many "add 10" and/or "add 1" I need to reach the velocity value I want for the button.
Anyway, one thing that helps me a lot is to create buttons on the MIDI editor to set the selected notes to custom velocity values. This way I can make a button for each intensity of my drum sampler. It becomes easy to choose how hard I want each hit to be without having to guess or memorize the velocity range/region that triggers each sample intensity.
While there are no actions that allows you to set the an exact velocity value, there are actions to 'add 1', 'add 10', 'remove 1' and 'remove 10' from the velocity. So I create a new action where I stack 13 "remove 10" actions (the max velocity is 127, so stacking 13 'remove 10' actions assures me that the value goes to 0) and then add as many "add 10" and/or "add 1" I need to reach the velocity value I want for the button.