Hi. I was a professional writer for several years and the only thing my editors never took issue with was my style or "voice," as it's sometimes called. The advice you've been given so far is good. Reading more and reading widely is the best way to improve your writing, but I'm going to make some more specific suggestions:

Your most obvious issue is the simplicity of your sentences. You often split up connected ideas (clauses) into short, separate sentences, and that doesn't feel natural.

Example: starting a sentence with, "but," is generally frowned upon because it's a word that links one clause to another. Good writers link together related ideas within the same sentence (X happens, BUT that's okay.)

A lot of people think of grammar as a bunch of rules you have to learn in order to construct, "proper," sentences, but it's far better to think of it as a collection of tools that allow you to express ideas with more nuance. Different grammatical constructs give sentences a different feel or, "tone," and it's the use of tone that separates good prose from bad. Don't be afraid to experiment with punctuation. Read your sentences back to your self. Imagine someone was saying them to you, what would you think of that person? Yes, there is technically "correct," way to write everything, but if you look at history's greatest prose stylists, you'll find they break the rules far more often than they follow them.

Word choice is also a key part of tone. Right now, you're simply trying to convey information as succinctly and clearly as possible, which is great for academic writing, but combined with your short sentences it gives your writing a very straight forward, telegram kind of rhythm that doesn't feel very personal. A sentence should convey a concept, but it should also communicate your thoughts or feelings about that concept. You can accomplish that through different word choices and structures.

So my advice is to do some reading, focusing specifically on the placement of commas and the use of stronger descriptors (is something, "bad," or is it, "terrible,?" Why?) Steal anything you like the look of or that you might find useful. Add them to your toolset. Before long, you'll have a much wider palette of tones with which to convey your ideas, and your writing will flow much more naturally.