This tutorial will not work in Photoshop Elements! You can only write actions in Photoshop.
So what is an action? Photoshop actions are recorded steps that you perform on an image; these steps can be saved and replayed on another image at a later date. They are great for your basic workflow. Maybe you like to do a curves adjustment, then a levels adjustment, then a color pop, and finally a slight sharpening on your photos for your album. Why not write an action so that you won't have to perform each of these tasks on each photo. These screenshots are from PS7, but the general idea should work in later versions of PS, and even Elements.
1. Open your Actions pane.
3. Click on your Action pop down menu, and this is what you should see.
OK, now you know what it looks like. So lets make a simple action that should work in PS and Elements. We will do a basic color pop.
1. Open an image. Make sure your layer pane is also open.
2. Click on 4, "Create new set". Call your set "Practice actions". This can be renamed any time.
3. Click on 5, "Create new action". Name your action "Color Pop" and make sure the set is "Practice actions". You can also assign a function key to operate this action. Say you make it F1. When you press F1 then your action will automatically run.
4. Press Record.
5. Image>Duplicate and name it Color Pop. This opens a duplicate image that you will work on. Your original document will be untouched and you can compare the before/after. This will also keep you from saving over the original!
6. In your layers pane, drag your background to the little "Create a new layer" icon on the bottom, or press Ctrl-J to make a copy.
7. Put this blending mode in Soft light.
8. Go to your Action pop down menu and click on "Insert Stop". A comment box pops up. Type "If happy with the picture, press Continue. Otherwise, press Stop, make changes (perhaps change the blending mode to hard light and/or change opacity of the layer), and then press play selection to flatten the image." Then click on "Allow continue", then OK.
9. Layer>Flatten image OR Shift-Ctrl-E.
10. Select 1, "stop recording/playing" on your action pane.
Your action should be finished! Now compare your before/after pictures.
OK, now some extra things. Say you are recording an action and make a mistake. No problem! Just go to the action pane and select "Stop recording/playing" and find the part of the action that should not be there and drag it to 6, "Delete". Go back to your image and Edit>step backward until you get back to where you want to be, and press 2, "begin recording" on your action pane once again.
You can also add things to your action after you finish recording. Just click in the action where you want to add something (Adjustment layer, etc.), press record, do that thing on ANY image, and press stop recording. You can also add "Insert menu item" without pressing record.
Now there are several ways to record an action. Say you want your adjustment layers set the exact way for every run. Then record your action and make the adjustments to your adjustment layers as your record. For example, if you want your Curves adjustment layer to have a slight S curve on it for every image, make that adjustment on your curve while recording.
However, perhaps you want to do an unique adjustment for every action run. Then as you are recording your action, click on "create new fill or adjustment layer" on your layer's pane, select what adjustment layer you want, and then just press OK, without making any adjustments. After recording your action, you need to click on the second little box (dialog on/off) to the left of that adjustment layer in your action pane. When the action runs, the adjustment layer dialog box will pop up and you can make any adjustments you want.
If you originally made changes to that part of the action (say set the Gaussian Blur to 5), then the dialog box will pop up with that setting, but you can change it while running the action. If you don't turn on the dialog box, then the action will run, without pause, and have the Gaussian Blur set at 5.
You can also enter a Stop while recording or after recording the action. For example, you can record a stop that says "Set the Gaussian blur to 5 - 10". So stops are used to tell people what they need to do in the next step (make sure you click on "Allow continue" or the action will stop!), or to tell people to stop the action, make changes to their layers, and then press play to finish the action.
When you add a stop after recording, just click where you want it in the action and go to the pull down menu and select "Insert Stop". If it is not in the proper place, then move it where ever you want after entering it. You don't have to press record if you use the action menu.
To save the action set (you can't save individual actions, just sets, so make sure you drag the actions to the set you want to save) just select "save actions" from the Action pull-down menu.
OK, hope this makes sense. Let me know if you have questions! This is just the basics, but it can get you started.