I have a few recommendations, but I am not familiar enough with how you prefer to do things so I can't say any with full confidence but two.

1: Use references, especially for proportions and size. It may seem basic, but "fundamental" is a better word to use. There are a number of ways to import images into Blender to use as references or even 1:1 scale blueprints.

2: Making a model in "pieces" (E.G. Limb segment, pelvis, torso...) and then joining them together when it's all ready is tremendously easier than doing the whole thing at once or extending the sculpt far out (under a significant majority of situations). It allows proportions and shape to be adjusted more easily without messing up nearby areas and also lets you focus on one thing at a time rather than if it will match the neighbouring bits' quality at every step. This also applies to vertex modelling and remeshing which are more of my expertise. If you're interested in trying out a different method, I would suggest trying vertex modelling. I know from teaching experience that it's not something for everyone, and that it has a few places where one might get snagged. Some vertex modelling tools/functions can help with sculpts too, like proportional editing.

You might have even done one or both of these already, in which case I suggest to keep practicing but with smaller models with a narrower scope. These could also be used as 3D references for future models, just like this one. Knowing what went awry now to change next time is just as important as knowing what went well now to repeat later.
I can say however, that what you have is a decent quality sculpt for your second model. A bit off in places but there's potential. The area from the knees to the shoulder is of notably appreciable shape.

Also remember to use incremental saves, in case you want or need to go back to an older stage of progress to revert or to look back on how something was done. Saving over one single file repeatedly is never recommended but it happens too often not to mention.