Here’s the tip:
Be subtle! A little goes a long way in Photoshop. You can always add more if you need it. Also, use layers. If you want to combine the effects of different filters, do so on separate layers. Changing the opacity of each layer will control how much filter effect gets applied to the image. Also consider using a gradient mask. If you apply a gradient mask first and then the filter, you can control which parts of the image are filtered and which are not. Lastly, experiment. Try different things. Step outside your normal range of actions to make something new.