It might not be all that obvious at lvl 50 but generally speaking it's better to heal through rather than Esuna dots. Keep Esuna for the debuffs you need to dispel like doom, or in some cases heavy.
When it comes to awareness, practice will make a huge difference. If you develop a good amount of muscle memory with your heals and become more familiar with the content, you'll have more time to look around and be more aware.
Generally speaking, putting your party list towards the center of your screen (near your character) is the way to go. The party list is where you live as a healer so you want all the important info around it. Placing and using the focus target info bar near your party list will also allow you to keep an eye on the enemy cast bars. That way you have your party list, your enemy info and your character all in one spot.
On top of that, turning off other party member's effects down one notch helps a lot. And of course zooming out as much as possible. Don't worry too much about what your party members are doing, that will come with time. Just keep an eye on the party list and yourself.