First off, let me say welcome to Dakka. (Maybe you lurk but you account is new today!

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Your stuff looks like solid tabletop work. The problem I have with the work you have presented is none of it looks finished. While showing off work in progress pictures is all well and good (Definitely a must for commission services) it hurts you when advertising your service. When you present yourself to your possible clientele with these photo's it begs the question what the finished product will really look like. Your portfolio should consist of your best paint jobs, even for tabletop work. Something that was painted in thirty minutes and would average a 4.3 on a scale of 10 would not be something I'd include. (I'm not saying that is what your pieces would score, I'm just using that score as an example.

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From the pictures you have posted I would say each piece is of a medium tabletop quality. Since you advertise you can do high tabletop, I'd accompany some high tabletop quality pictures. If one of these photographs was of a high tabletop piece, put a note on it. This way a reader/potential client can distinguish the various levels of work.
I'd love to see more work from you, I think you have real potential, if you just work on a few more things.
One thing that will go a long way with commission painting is a great photography set-up. For a long time, the set-up I used was sub par. It worked for what I needed but now that studio work is picking up, I've upgraded. I guess I should say downgraded. My current set-up cost a fraction of the old one and has improved the results tenfold.
Roman has written several great tutorials on making simple professional quality photo set-ups and how to photograph miniatures.
http://massivevoodoo.blogspot.com/2009/10/tutorial-overview.html#photography
I also recommend this blog for your enjoyment. The author was a studio painter for Privateer Press and is a good friend of mine. She has written several posts with helpful insight into commission painting and how to be successful doing it.
http://arcanepaintworks.blogspot.com/
I hope my advice helps you with your painting and business venture! If you have any questions or want to talk shop, feel free to
PM me or add me on Google+. I can be found with my email, ExiledMiniatures@gmail.com
Cheers
Aj