Have you ever missed a good photo because you had the wrong settings on your camera? This is one thing you could do:-
Suppose your going on a forest walk and hope you’ll see a red squirrel. Before you set off put your telephoto lens on, use a large aperture to help blur the background, eg: f4.5 think about light levels and raise your ISO enough for a reasonably fast speed eg: 1/300th. Chances are you’ll be hand-holding a long lens.
Then test this out at the start of your walk. Focus on a branch and take a trial shot. Now examine your shot by reviewing it and magnifying to make sure your image isn’t blurred.