My suggestion would be to always sharpen and blur with the brush, yeah!
Only use the filter if you want blur to an extend that the brush can not do.

As for colour, that's going to be all you, buddy!
Just play around with it. I've quickly read through your tutorial to see if you did the colour as I expected you to do it, and you did. Nothing wrong with that, other than that it gets bland over and over again.

It's quite simple to counter this, though.
Just add a few more layers after the colour correction and simply paint in streaks or bulbs or any other source of light in a different contrasting colour and you'll be set. Play with layer styles to see interesting effects, sometimes the layer style you never expect to be helpful can be the one you need in that situation.

I'll be around ;]

I'm gonna have to read up on colors, I know very little when it comes to what goes good with what and that stuff. I get what you mean. I'll try to make more art more frequently to get practice, as at my current pace my next work is going to turn up some time around september, lol.

Be careful, studying colours is a lot of fun.
You might get hooked and turn into a hermit ;]