Ok, so the least overwhelming way (imo) is to work on several core things simultaneously, and just gradually chip away at it all. I know that probably seems more overwhelming, but once you have a rhythm down you'll be okay. I'm going to roughly lay things out and if you want more specific details please ask. I will include the 'summary' first but see below for some details or ask me/anyone/Google.
- Work on your class/order hall campaign (all quests/chain starters are offered in your class hall, ie. Trueshot Lodge for hunters). You can blast through a lot of these quests really quickly.
- Open up the achievements for Broken Isles Pathfinder (pt 1 and pt 2) in the achievement tab, and work away at any parts that you feel like working on (eg. exploration). The Pathfinder achievements are required for flying.
-- Chip away at quests in Suramar to make progress towards Good Suramaritan as this is the most involved part of Pathfinder.
- Try to do at least one emissary quest a day (you need the rep for flying, and the rewards are p good).
- Keep Artifact Knowledge research orders rolling (with the npc in your class hall).
- Work away at the Breaching the Tomb achievement when you can - this is needed for taming feathermanes/getting your class mount; Note that many of these quests aren't available until you finish your class hall campaign.
- You want to work on Broken Isles Pathfinder pt 1 and pt 2 (they will show up in your achievement list - have a look at what the requirements are). Both of these achievements are the requirements for Legion flying.
-- Good Suramaritan is the most involved of these. Just chug away at the quests you get offered in Suramar. I recommend setting your hearthstone to Shal'aran in Meridel (Thalyssra is the inkeeper) while you are working on Good Suramaritan, but that is obviously up to you. I recommend doing nearly every quest you can see in Suramar, because while some aren't required for Good Suramaritan, you do need rep in order for chains to open up to you.
- I recommend doing at least one emissary quest a day, as rep is required for Pathfinder. Which ones are active show up in the bottom left of your map (in Broken Isles). You do not need to accept or pick up emissary quests. Basically, you have to do four world quests for one of the factions (eg. right now I think you can do Dreamweavers (in Val'Sharah), Valarjar (in Stormheim), and/or Wardens (all over - on the world quest in the map it will say Wardens - they are typically just killing one boss/mob somewhere, or the falcosaur quests)). Once you have done four world quests you turn in your emissary quest with the quartermaster of the faction (which will automatically show as completed once you do the four world quests). You will see the '?' on your map where they are located. If this part is unclear please let me know. Emissary quests give 1500 rep (without bonuses), an ap token, and a treasure chest. Emissary quests are up for 3 days at a time, and you can see how much longer one will be active by mousing over it in the bottom left of your map.
-- You can also get rep from finishing up side chains in zones, dungeons (I think? I don't do them a lot), and rep tokens (once you have high geared followers you will get rep missions), and world quests (note that world quests are active even if an emissary is not active in that zone).
- Khadgar (in Dalaran) should offer you a quest to go to the Broken Shore. Do it. It involves a solo scenario that can be a bit tough in low gear, but note that if you stick by npcs you will buff them ('inspire' them or something) and they will do a lot of your work for you. So it is do-able with low gear. It is okay if you die in the scenario too, as you can keep going where you left off. Alternatively, you can replace some of your sub-800 gear (which you probably have if you are fresh 110) first if you prefer. There is a vendor on the broken shore (specifically, the main hub) that sells gear tokens (dauntless) for 400 nethershards each - if you have really low gear this is a good way to catch up. You can access the vendor before doing the scenario, you just need to get to broken shore on your own (or ask someone for a ride). You also need rep with the broken shore faction (Armies of Legionfall) (in order to earn flying) which you can get from turning in resources (as you quest on broken shore the mechanics of this will become clear) HOWEVER I recommend waiting until you are done your class hall campaign as then you can work on Breaching the Tomb, and each step of this gives 1500 rep which is swell.
- In your order hall, get artifact knowledge research going, and keep it rolling. Artifact knowledge is a multiplier that increases your artifact power gains, so it is good to get it up there. At level 110, you should be sent to the npc via a quest or they will offer you a quest in the hall. Once you research your way to artifact knowledge 25, a quest 'The Broken Shore: Investigating the Legion' will appear from Khadgar in the Broken Shore. This will allow you to continue research to artifact knowledge 40, which is the current max.
* Note: I thought that all 110s could immediately get artifact knowledge 26, however my friend who just joined and got to 110 could not get ak 26 right away and has to do research *pouts*.
- In your order hall is also where all quests and quest chain starters for your class hall campaign will be located. Some quests aren't mandatory for for the class hall campaign (you can ask me or others or consult wowhead about which ones specifically are not required). You can blast through a lot of these quests really quickly (sans the mission ones which aren't too long anymore) and I recommend doing this. You will need to complete this before you can do much the Breaching the Tomb achievement which is required for feathermanes.
- Once you have completed your class hall campaign you will want to work on the achievement 'Breaching the Tomb'.
- Demon invasions spawn every ~18 hours or so in either Val'sharah, Stormheim, Highmountain or Azsuna. They are a good source of nethershards and gear if you are gearing up. They are just special world quests active for ~6 hours. When you enter a zone currently being invaded you will be offered a quest to do four of the invasion world quests. If you do this quest, then you will be offered a couple more quests (regular ones, not world quests) which will culminate in a 3 person scenario. The gear in these is also p good for gearing up, and the final boss of the scenario drops quite a bit of nethershards.
- Others might have more advice.