Why aren't we commenting?
Because it is difficult to know where to start when trying to offer constructive criticism to someone who is new to the sculpting game.
Also, slightly larger pictures may help.
That said, I am also just an amateur but I will share what I think may be useful.
I recommend building the body first and getting the pose and proportions right before you even think about adding details. You are trying to run before you can walk and need to focus on the basic frame. What is the good of piling loads of effort into wonderful detail if your basic miniature is poorly posed or has bad proportions?
Look at anatomy. Stare at it... study it... learn how limbs work... learn how muscles attach... learn where the muscle groups are... use all that information to sculpt a figure and then smooth all the bumps out to make it more like a skin covered person than a muscle covered skeleton.
If you have areas you are not confident with (hands, faces, feet etc...) get a bunch of wires together and sculpt lots of them... when you think you are happy, sculpt a lot more.
Looking at the three sculpts, the guy on the right appears to be the best of the bunch (from the small picture). His shoulders need to be a bit broader and his feet a little bigger but apart from that, he doesn't look too bad. I can't tell what his head or the one in his hand looks like so I can't comment further. The guy on the left is the next best but he is suffering from the slim shoulders and small feet issue as well. I can't really tell much more from the picture but his head seems to lack a bit of bulk to the rear (the brain-pan)
The lass in the middle is little more than an armature however, the abdomen / torso area will cause you problems because you have not allowed for any ribs, a waist or hips. If you look at a picture of a naked woman you will see that although it takes time to stop staring at her heaving bossom, there are actually ribs, a waist and hips there too... and you need to take that into account or your sculpt will end up cone shaped with a pair of boobs.
The most basic things that a sculptor needs in his toolkit are:
3. More practice.
4. Even more practice.
5. Did I mention practice?
6. Take heed of advice and don't get upset by it. If you think the advice is shit... ignore it! Move on.
7. No sculptor sculpts the same way as everyone else. Find your style (through practice and patience).
Learn to work the putty smoothly, ensuring that you keep your tools lubricated. Work out how much pressure to apply. Learn how much you can sculpt in one go without pushing things in the wrong direction because you are trying to do too much in one go. Experiment with clay shapers (they are great for smoothing putty). Get good at sculpting a figure on an armature BEFORE yo turn it into a miniature. It is good practice and will enable you to understand the anatomy and proportions much better.
For the record, I did exactly as you are doing when I started sculpting 30 years ago... and I got told to work on the foundations before sculpting all the details. I got stroppy but I took heed and now, my end results may be lacklustre but at least the proportions are right