This is one of those tips that you'll either use all the time or never. Press Command – Option – Shift – E (PC: Ctrl – Alt – Shift – E) to Stamp Visible layers, which creates a new layer on top of all the visible layers below. This is really useful when you want to apply a filter to the compiled image but want to keep all of your existing layers intact. The only downside is that it can increase the file size dramatically.
Good Tip, I use it all the time.
Aha, that’s the one I have been looking for….