Space is often referred to as white space, and gives the design some breathing room and the eye a place to rest. An ill use of space (or perhaps a very well planned out use) can make the design feel crowded and claustrophobic. Too much space, however, and the design can seem unfinished, like it’s missing something. Once you know the rules (for any of these elements, really), you can also experiment with breaking them in order to push a different emotional response.
Not so much of a ‘tip’ but more ‘helpful advice’… but yes you heard me, do not use the filter gallery. Design is not filter effects and it never will be. Also please resist adding lens flare to your work, as well as rainbow gradients, embossed type and drop shadow unless you know how to use it well. You may want to check out 15 Signs Your a Bad Graphic Designer. NB. Rules can be broken.
Once you master the blending modes in Photoshop you can pretty much ‘own’ photoshop. Open up the layers palette, select a layer and click the downwards arrow where it says Normal. Try experimenting with different blending modes on different layers, put layers above or below other layers, change the opacity and so fourth and you will be amazed!
Practice. You can do this by doing tutorials or watching videos or experimenting on your own. Practice, practice, practice!
In my own personal experience I have found that if I find a design piece or style that I really like, I search the net and magazines for tutorials on how to recreate that effect and try to adapt it to my own personal project and style… I find this a great way to learn. Also if you ever need help, check out Adobes Help function in the programs and also write questions on forums (or blogs)… people will be more than happy to help you out!
Is this article worthy of a stumble or designfloat? 
How many of these did you know about?
This post comes after hearing the reactions from some of my fellow students in class when they found out about some of the options available that they never knew about.
After you make a selection in Photoshop you can easily edit the selection using refine edge in the top toolbar. You must try this out, it is very useful!
I am amazed by how many people do not know about these tiny little arrows that hold so many more options! These tiny arrows are pretty much on every tool bar across the whole Adobe Suite. I assure these arrows will open you up to a whole new world.
If you right click on a layer in the layers toolbar, and then click blending options this will bring you to a whole vast array of effects that will keep you busy for hours. Use these options very sparingly.