I’m a level 79 Noob (I think the cool kids type it n00b)… I make mistakes ALL the time.
I can tell you what some of my big problems were (and sometimes still are). I started with Arcade - and when I started ARB, I wanted to fight the D-20 aggressively, just like in Arcade.
I had to step back and examine how the Mustang actually performs - and its acceleration/energy generation are not good, particularly at low speed. Combined with mediocre MER, you get a plane with a low sustained turn rate and very limited ability to maneuver in the vertical… but very good handling at speed (with the exception of the rudder) and good speed in a straight line.
Sticking an engagement long enough that it becomes and engagement with an energy disadvantage or starting an engagement from an energy disadvantage (or parity), particularly against a more maneuverable plane, isn’t likely to end well… sometimes you can trade altitude for speed and escape/reverse… sometimes not.
The Mustang pilot needs to be very deliberate about how they setup their engagements… and then they need to finish effectively. The Mustang is excellent at going fast and flying straight… if you’re doing those things, you’ll find more success than doing things the Mustang is not good at (going slow, turn fights).
The Mustang isn’t particularly good at climbing, but I climb anyway… because sometimes trading altitude is the best way to go fast. I do something the Mustang is mediocre at to later do something the Mustang is good at.
I had a match a couple weeks back now where a D-30, my D-10, and one D-20 clutched against something like 6 or 7 bandits… because a group of semi-competently flown Mustangs is oppressive. That D-30 ended with like 7 aerial victories, we each had 2/3… so the three of us accounted for 12 frags. I spent a lot of time baiting for that D-30, actually…