One of the first things I do when I reinstall or updgrade photoshop is add a few shortcuts.  There are 3 general tasks when using photoshop on a daily basis that I found myself doing, that did not have shortcut keys:

Transform Selection, Create New Guide, and Making guides at 0%, 100%, and 50% of the canvas.

1. Transform Selection

I use this one often.  Unfortunately, right now I can’t think of any good examples!  Anywho, I decided to use Ctrl + Alt + ‘ for this one.

2. Add New Guide

Although I do use this one less now that I have created an action to automatically add 0%/100%/50% horizontal and vertical guides (next shortcut), I still use this shortcut on occasion. Plus it will make things go faster for setting up the next shorcut. For this one I use Ctrl + Alt + ; If memory serves, this key combination is already taken, but the button is right next to the shortcut above, plus default key assignment is something I rarely use.

3. Press F12 to automatically get 0%, 50%, 100% Guides Both Horizontal and Vertical

I can’t tell you how long I wanted this one, but could not find a solution! In my defense, I never really looked very hard, but finally got fed up and figured it out.

I like this one because I often want to create shapes for example, and for some reason they don’t like to snap to the edges of a document unless there are guides there.
This is also handy if you want to add in bleed to your document, yet want to keep track of where your trim line will be.

This one is a little different, but once it is set up, all you have to do is hit one key (in my case F12) and it automatically adds in all 6 guides.
The first thing you need to do is make sure your ruler is set to percentage. This is VERY IMPORTANT and is the key to making this shortcut work. If you cannot see a ruler, press Ctrl + R and it will show up. Once there, double click the ruler and select “percentage” like so:

Now let’s set up our action! If you do not have the actions palette open, press Alt + F9 to open it. Select “Create new action”, and use the settings I have below. Feel free to call the action whatever you want. I called mine “Awesome Auto Guides”. Once it’s created, make your 6 guides using the shortcut key we already set up. When you’re finished hit the stop key.

That’s it! You can test it by first clearing your guides (View >> Clear guides) and then hitting the F12 key.

BONUS – Crop and Trim shortcuts

Creating the three tips above made me realize that I most definitely need to create shortcuts for “Image, Crop…” and “Image, Trim”.
I’m really kicking myself in the face at the moment because I didn’t I think of this sooner. I use both commands ALL THE TIME!
So I went ahead and created 2 new actions, just now, for crop and trim, assigning the shortcut keys F10 and F11, respectively. To get the crop action to record correctly, you will first have to make any ol’ selection with the marquee tool before recording your action. SWEET!