Sure skinning is fun, so go ahead and be creative, let your imagination come out and play like a child, that feels good but before you go and share your work with the rest of the community stop for one moment and consider the usability issue. One have to think that actual people out there will be using the stuff, actual people that are playing games (StarBlaze 2 ), using facebook, working with spreadsheets and who knows what else
Below I present you with my shame. My very old works that I was convinced were top-notch back then, ok go and laugh

Can you imagine someone using that on daily basis, OK that TT theme was not that bad, my point is on that memory meter which is so anemic and stupid looking.

Common usability problems are  wrong kind of fonts, typography is really important. Skinners should avoid using obscure and odd fonts,  I think system fonts ( Windows XP fonts) are really up to the task, sure I like some Vista fonts but we should think of users that are running XP. If you decide to go with some other fonts that are not shipped with OS you should consider including them with your skin (theme) but then you must think of copyright and such stuff. All menus and elements that contain text should be readable.

Transparency is the big issue also, have a look at my first Vista inspired theme for Aston

Yes kind of nice but if you look at the Panels element (subitems), think how would the letters look if the darker wallpaper was applied. Yes Vista uses transparency but back then I though managing the Opacity level was good enough. Guess what? it is not. Vista has transparent start menu, titlebar and many elements more but is not just that, Vista designers used a neat trick and placed one blurred layer behind so it is transparent but it is also blurred so the text is much more readable.

One thing that annoys me the most is theme made for one wallpaper, the one that comes with the theme, but if you try to use some other background theme becomes pretty much well…..unusable. And drawing theme elements on the wallpaper itself , really even worst idea so don’t do it…please.

It is also important not to use elements that stand in the way of regular computing, like too big start buttons (talking about Vista styled buttons) that can cover the part of applications status bar ad such.

One thing that I cannot understand is how people make dozens of elements but do not include or do not think of need for  having so called visible hover state for the menus or icons. It is important to have that and it does not require making of totally new element, usually font color change or style would do just fine.

OK  I’ll stop here for now but this is not over…yet.