Sure! Let me see…
OK, nice stuff! Critique is quite a detailed thing, BUT on a sculpting front I’d say you’re definitely going in the right direction and just keep keeping on, you’ll keep improving. For leaves and things like that, I always like to draft the backs of them inwards to give a feeling of lightness and delicacy. If you just make the sides flat they can look a bit artificial which slightly undermines the other good work you are doing.
Are you using solidscape rapid prototyping? You might make your life easier and cheaper by printing on envisiontec. It has a much smoother finish without losing detail. Mark@Rapid Models in Birmingham can help you there. www.rapidmodels.co.uk.
When it comes to hollowing models, personally I prefer a more consistent and technically correct method of hollowing than just sculpting. I would therefore recommend hollowing/offsetting surfaces instead using a polymodeller, CAD or STL editor. This will mean you have a sensible thickness for setting 1.2mm approx depending on Pavé stone size.
From a design perspective, which is of course purely subjective, for things like your animal rings, I would consider doing something different with the shanks than sort of draping a nicely sculpted head over a standard D-section ring. If you really want to use a D section shank, I’d consider adjusting the proportions slightly.
Finally is on finishing, it’s a difficult business trying to get things finished well - especially in the UK, but a little more time and care in prepping the master goes a long way to big improvements in the finished article. I don’t work at the bench myself, but where a really excellent goldsmith can make your work shine, a not so excellent one has the opposite effect.
Hope that helps!