Drop shadowing is a great way to make your elements sit out and make your viewer take notice! It's simple and easy to do, plus you have two different options to do so: Paint.Net Drop Shadow and Lokas 3D Drop Shadow (plugin).
Again, this is my tag that I created for this tutorial. As you can see, it's boring and flat.
Highlight the layer you wish to drop shadow in your layers box. Mine is the fish.
Do the following from your upper toolbar:
This box will pop up:
I adjusted my settings and now my fish looks like this:
1.) Highlight layer in your layers box.
2.) Follow steps to find drop shadow.
3.) Adjust your settings and click "OK".
So, I drop shadowed all of my layers but I found that I didn't like how my tube drop shadowed. It looked too blurry at the bottom.
So, I go back and "Undo" my last action, like this:
I reset my settings to my liking and try again. This is what I got:
NOTE: This is so cool! If you are wanting to drop shadow with the same settings you first put in on each layer, you do NOT have to keep pulling up the settings box.
Your "Effects" box will show the LAST thing you did on your design and you can simply click it to repeat the same process. Like this:
Remember, it will keep record of the LAST thing you did. So, if you last thing was "Alpha Mask", "Repeat Alpha Mask" will be at the top.
You can now see how well my elements sit out from my design. Play with your settings to make the drop shadow darker, longer (Offset X & Y) or wider (Widening or Blur Radius). It's always fun to see what each little tweak will do to your elements.