Just back reading after finally getting the chance to have a browse.
This is a great topic. I started sculpting about 12 months ago. I found the best way to start was on existing figures by doing conversions. conversions in the sense of arms, hands, redoing equipment etc. I have basically spent the 12 months concentrating on those aspects and only now found myself getting more proficient at it. I have now started doing helmets/head gear. Doing things in small stages lets me concentrate on one aspect to a point i am happy with before moving on. I do do beards etc, but am yet to try faces. But after reading this thread, i will certainly be having a go sooner rather than later.
as to tools, well i do not make mine, i use the clay sculpting set as Alex showed and just a basic sculpting set. I am not doing overly fine detail at this point, but will use finer tools as i develop.
The key for me is taking small steps, trying to sculpt a whole figure straight off can be frustrating, i tried it.
Below is some of the conversion work i have done. I actually produce my own figures (hence wartime). I will then rework some used masters or commissioned dollies to make the figures i want. These are wargaming figures, not specific modeling.
I commissioned a series of dollies for Vietnam period. had them cast and did my own adjustments from there. Some with sleeves down, some up, added a watch to figure 2nd from left on left arm. I have VC, NVA (early and late) and Australians still waiting for some attention.
Here are some modern insurgents i reworked and or converted from some of my own castings.
Here is a more recent work up adding a current model helmet to a modern Australian Master.
My sculptor uses the "Brown Stuff", i used "Green Stuff" up until the last couple of weeks and now have been quite taken by procreate.
Anyway i hope this contributes.