The vast majority of his personnel choices have been a "huge mistake". Most were chosen based on how well they kissed his ring, not how well they could perform their duties.
I think you’re mistaken. When he first came to office, and not knowing anyone in Washington circles, Trump relied heavily on long time Washington hands and seasoned professionals like Reince Priebus [sic] to advise him on WH staffing. We’ve all seen how that went.
But, Trump recently let it be known that going forward he will be relying on his own instincts to select who to hire, so we should be seeing more folks loyal to the president and, well, less swampy.