First thing: If I started to type out a complete guide to Colour Management (CM) in
PS, I'd still be here next week, (mainly because I'm a slow 2 finger typist). Read everything in the
PS manual/help files - there's a lot of good info there. Have a look at the following site & read some of the links under Colour Settings:
http://members.ozemail.com.au/~binar...V_links.html#D
CM may seem like a big & complicated subject, but mostly it just takes reading an article that describes it in a way that makes sense to you - the light above your head goes on & everything drops into place.
Here are a few pointers to help with your immediate problem:
When RGB images are passed around outside a CM workflow, e.g. on the web, their appearance can vary enormously. That's why we need CM. One common problem is images in AdobeRGB being handled as if they are in sRGB or monitor RGB. If your images are in Adobe RGB & you're sending them to a friend or putting them on the web, try converting to sRGB first.
For CM to work well, or perhaps at all, you need to have reliable descriptions (Profiles) of the colour performance/abilities of all devices in the workflow. You can start by producing a profile for your monitor (Adobe Gamma on Windows, System Prefs > Displays on a Mac), do ensure that you're lighting conditions are good, the walls of your room are neutral, etc. You should find the results are helpful, but bear in mind that our eyesight has a highly effective white balance system, thus we're not that good at judging colour neutrality. Hardware calibration will give you much more consistent results, if you can justify the cost of a suitable package.
I note you have an Epson printer - I've always found the profiles they provide for their papers/inks are very good, but again a custom profile is certain to improve your results. As you don't mention any problems with printing I'll leave it at that!
If you have any specific questions, just ask. (But I'm not in the forums very often...)