Next, track down anything you overuse. Me, I tend to employ too many em-dashes and semicolons. I then scroll through my document, and can see where I have too many of them close together. Also worth hunting down are exclamation marks. I used above are okay for a column like this, but if you're writing real adults in real situations, you may want something harsher.
Most writers notice during proofreading if they've started two consecutive sentences the same way.
But it's also bad form to start two consecutive paragraphs the same way, and that's harder to spot. Again, your computer can come to your rescue. You'll end up with almost all of your paragraphs as single long lines, scrolling off the right-hand side of the screen. You can then compare how each paragraph begins. If you didn't notice that yourself, this technique is for you.