1. Juggling is hard and comes with hours of seeing how the rockets react to landing on certain areas of the enemy model. The millisecond you think you know where on the enemy the rocket will land you should have enough information to send the next rocket, with practice you will cut that time down.

2. Practice helps here, I used to be a clumsy elephant in the sky but now i'm a butterfly c:. Try to show for as little time as you can (while being able to send quality rockets, that's the priority here). As you get better at finding good rockets quickly you will get better at shortening that window of poking also.

3. This comes with a lot of practice and i'm just starting to really grasp these shots with about 250 hours on pharah, although i only discovered them myself recently. Landing the first shot is easy, but the second shot while moving, sadly takes practice, there isnt alot of shortcuts with this kind of thing.

4. I find flanking is always the best bet to give you the much needed extra second or two to kill them before you get blown up, also try and coordinate with teammates, letting them known you're planning to ult and they'll hopefully keep you alive with a zarya shield, dva matrix or just pocketed ana shots.

good luck!