Process snapshot!
I love this trick for getting just a little edge colour on complicated shapes using clipping mask, layer mask, and gaussian blur! These steps are for Photoshop but a similar principle should work in most programs.
The object whose edges you're highlighting needs to be on its own layer.
Create a new layer above your Main Layer. Select the new layer, then click and drag THE MAIN LAYER to the [+] sign at the bottom right of your layers palette. This will give your new layer a layer mask matching your Main Layer's shape. Select the layer mask and reverse it using ctrl+I on your keyboard (or by going to Image > Adjustments > Invert).
Fill your new layer with a bright colour, then apply the layer mask.
Make your new layer a clipping mask above your Main Layer. The colour will alllllmost disappear - this is where Gaussian Blur comes in!
With your new layer still selected, go to Filter > Blur > Gaussian Blur and adjust the slider until you have the amount of blur you want. Apply the blur!
Last step: use Image > Adjustments or layer opacity to adjust your edge colour until it's just right.
Unlike making a selection and then using Stroke, this method produces a strong and reliable colour. The double mask also ensures that even small unconnected areas have the technique applied to them. It can be a pain to shift+select too many small areas!













