First, select an output from the Output dropdown menu in the Profile Settings pane. This could be the Clipboard, an output to a particular program, or even straight to a file.To skip previewing your capture in the Editor, deselect the Preview in Editor option in the same menu.Holding <CTRL> while moving a selection created with the selection tool doesn’t move the selection, but instead makes a copy. This copy flattens after you’ve moved it, just like a normal selection.
Rule of thirds: The human eye finds some images more interesting than others. Dividing an image into thirds shows you where the most interesting parts of your image should be. Divide your image into thirds both horizontally and vertically, creating nine boxes. Try placing things like callouts, arrows, and text along those lines for maximum impact.
Color selection: Use complimentary colors (colors located opposite on a color wheel) in your effects to create a look of cohesion in your image.
Think about context: What do you want your audience to look at? Is it important that they see your screenshot in the larger context of what was on your screen, or is it better to trim all that away and just show the exact window or button that you want to call attention to? Deciding may help your image communicate your message better.