Very good tips here already! I will elaborate on a few things off the top of my head.
Tip #1: Try to position yourself above your enemy before attacking.
Too often I see BnZ attackers (someone with a big energy advantage) dive down to the level of their target from 3K or more away to chase them down. They are then attacking only with a speed advantage and no real positional advantage. They are also expending a good amount of potential energy just getting to the enemy rather than using it maintain both an energy and positional advantage (above the enemy). If you can be patient and fly to where you are above the enemy (or at least inside their turn radius) first before attacking, you will accomplish several things:
1) Your vertical attack will get on the enemy faster, giving the enemy less time to react
2) Regardless of which direction the enemy turns, you can simply roll to change direction quickly and easily position for lead pursuit and a shot attempt
3) Your enemy will have a harder time pulling nose to nose for a HO (as they will need to pull up and lose energy to HO you)
Tip #2: Often a defensive enemy will just try to pull his nose up to you to HO. You will need to recognize when your enemy is pulling up to meet you nose on. When you see them pulling up for the HO, simply start a spiral climb to keep the enemy nose-up and wait for them to be near stall -- essentially converting your attack into a rope. Some aircraft regain E quickly, so be on the lookout for the nose up HO from that defender more than once (if you don't rope him and kill him the first time). As Wiley said, usually what a player tries once, they will do again, so anticipate the same move more than once.
Tip #3: Become good at using the high-yo-yo. When an enemy makes a break turn to defeat your BnZ shot attempt, the high-yo-yo is a good choice to 1) climb back above the enemy while 2) keeping them in view and 3) positioning you quickly make another attack -- keeping the pressure on just as has been suggested above.
You don't need to push for a shot every attack, as the objective is to get them to turn, lose altitude and burn energy so you can attack them again while they have less and less energy. Using the high-yo-yo aggressively is very good for this. Often my first attack is not even about getting a shot, it is about sizing up their energy and how they react so I can maneuver accordingly for the next attack.
Tip #4: You can always get with a Trainer in the Training Arena and BnZ us while we give you tips. This might be the fastest way to learn a good feel for some of the items mentioned above.
<S>
Kingpin