I am talking by my own experience running painting courses in Spain and here in Belfast (where I live now). I can see you are accurate, good brush strokes, very neat looking minis and overall, your minis have always a good finish.
I would start working on highlighting, as seeing you have the potential, you are at that moment when you need to risk and try go further when highlighting to take your minis to a different level. This is adding depth to any colour you use, and you get to that through a controlled darker base.
As an example, if you want to paint red (say Mephiston red for example), You don't start with that colour just like that. Try mixing Mephiston red with a dark brown such as Rhinox Hide or similar. If you have a wet palette, which is something I highly recommend, you can visually "measure" the level of contrast you want the base to have with respect to the main colour (Mephiston) high, medium or low contrast.
Then, as you are using a "darker version" Mephiston for the base, when you start with Mephiston, you will not cover the base entirely, you will always leave a bit of the base colour visible to get the depth you need, and by using always the same (main) colour, you get a much more organic look.
Then you will add Blazing orange or similar to Mephiston gradually with every highlighting step, and paint a smaller area with every step, always leaving the previous step visible, if that makes sense.
This principle applies to any other colour.
I hope this isn't too confusing. It's always better to see it done, but I hope this helps. : )
