I play an ungodly amount of Ana, and I gotta say that the general “tips” I’d give really depend on your enemy’s team comp and whether you’re playing attack or defense.
If you’re playing defense and/or the enemy team has no widow or flankers, you should play her further back (IMO the best comparison I can make is slightly further back than where a soldier would be), stick to high ground where you can, heal from a distance, and stay safe. Once you get good at that distance, landing grenades actually isn’t that hard if you can predict where a fight is going. Most of the time, I hit 3+ people with my grenades if I’m on decent high ground with a good angle.
The biggest downside at this distance is that your sleep darts are way harder to hit. Purely because of the distance and the fact that they move so slow, you’re going to miss a bunch of darts that, realistically, we’re just luck. Even if you aim well, when you’re far enough back, people have moved too much by the time your dart arrives. So, for the most part, I think you should just hold onto it so that you’ll have it for easy-to-hit, but important instances like charging reins, ulting roadhogs or pharahs, etc. When you’re playing this way, don’t try to use it aggressively to get picks, use it when the enemy is pushing in with something you can shut down.
This is how I play Ana most often; since she really doesn’t have any ability to protect herself once the notoriously fickle sleep dart is down, I find that it’s best to rely on distance and the geometry of the map to keep you safe. Stay calculated, and, for the most part, far back enough to utilize your scope. I find that most people think Ana shouldn’t be too far away, and I agree that her kit works best up close, but at least one interpretation of her problems is that her kit isn’t enough to keep her safe. I’ve found that I do better relying on my scope than relying on my kit.
And so you know, you WILL miss more shots playing further back. I find that the trade off is well worth actually being ALIVE at the end of the fight, but your numbers will be lower than most other Anas. My scoped accuracy is generally in the high seventies, but my unscoped accuracy is normally in the high 60s since I don’t generally use it to heal - mostly, I use unscoped shots while i’m fighting off a dps that got close to me, or trying to pressure back an enemy tank while moving.
On the flip side, if you’re on attack or if your enemy has flankers, A) if you aren’t really killing your sleep darts, you should seriously consider switching to Moira. Unless you’re hitting the VAST majority of your sleep darts, Ana just can’t survive under those conditions. You’ll get pressured, forced to use your grenade on yourself, and then picked apart because you can’t get away.
B) but if you ARE doing all right as Ana (or your team really needs access to the antiheal) then you want to play up close behind your tanks (similar to the distance a mccree would be at). The key to making this distance work is to take an “L” formation. You want to have line of sight to your tanks, but you don’t want to be able to see the enemy team (because, obviously, then they could see you.)
This is where Ana becomes a TOTALLY different playstyle. Counterintuitively, if this is the way you’re playing, your job as Ana is to, yes, keep your tanks up, but just as importantly, you want to use your kit to make openings for your team to get a kill. Anti heal and sleep dart are both insta-kills if your team follows up on them correctly, and the thing about Ana is that, at this distance, the longer the fight lasts, the worse off you are. If the enemy team is allowed to engage on YOU, they will win because they’ll swarm you and you won’t be able to get away. Which means that YOUR team needs to engage on THEM first. A sleep dart on an enemy dps out in the open, or an antiheal right when the enemy tank’s shield goes down enables your team to go in, get a pick or two, and prevent the enemy from ever having the opportunity to dive on you. Sometimes you’ll need to use your name to save a tank or a sleep dart on an enemy ult, but for the most part you want to be aggressive and looking to create opportunities for your team.
In summary, take an L formation that allows you easy sight to your tanks, keep pumping heals into them to keep them topped up (using unscoped shots to ensure that you stay something resembling hidden - if enemy dps see a bright purple beam, they’ll know exactly where you are.) Focus on keeping your team topped up, but constantly watch for an overextended dps to sleep or a group of unshielded enemies to nade.
As far as the healing to damage ratio, most DEFINITELY focus on healing, but in my experience, the best Anas weave more damage into their rotation than you’d think. I’d say about 80% healing, 20% damage (note that this is easier to do when you’re playing farther back and have a wider field of vision - another reason I try to play further back when I can).
The key to doing effective damage is this: you shouldn’t be trying to get kills by yourself. Trying to take a target from 200 to zero takes too long, doesn’t work most of the time (the tiniest bit of lucio healing or a mercy that’s actually paying attention make it essentially impossible), and there’s the strong chance that someone on YOUR team will get picked while you had tunnel vision. Instead, you should be adding little bursts of damage to the target that your dps is fighting. Ana’s damage isn’t that strong on her own, but it can REALLY surprise a 200hp hero that was focused on a duel. Make sure that your teammate is pretty much at 100%, but once they’re mostly full, you’ve got time to take one, quick snipe at the enemy before going back to healing. Once you’ve practiced enough, you’ll get a feel for when your teammate has enough of a health “cushion” for you to throw some damage into the mix. When you’re good at it, you’ll be surprised how many eliminations you’ll get. Don’t take duels or chase kills on your own - just pop in your damage every once and a while once you see a chance to really pile on.
…wow, this was a really long post.