Materia:
If you have a bunch of materia or materia clusters lying around, it can be worth it to transmute your materia at the launch of Evercold. The goblin where you unlock materia melding in Central Thanalan is where to go; you can trade 5 materia for a random materia that can be the same grade or one grade higher than the lowest level materia you put in. Two important notes: 1) the materia you get out will be different from all 5 materia you put in; 2) the materia that you get out can be crafting or gathering materia in addition to combat materia. Trading [piety materia XII, tenacity materia XII, spell speed materia XII, skill speed materia XII, determination materia XII] could output a valuable grade XIII crafting or gathering materia, which will either be useful to you (if pentamelding) or sell well on the marketboard.
Rested XP:
On launch, if you’ve been capped at omni-100 for months (like me), you’re going to have a bunch of rested XP. If you rush MSQ, this rested XP is going to immediately be spent on the job you are doing MSQ on. That job is going to reach level cap long before the end of the MSQ, so this is a bit of a waste. If you want, consider spending this rested XP elsewhere before diving straight into MSQ, whether you want to spend it on the new jobs or on a job you HATE and want to play as little of as possible.
Avoiding Spoilers:
Do yourself a favor and filter out shout and yell chat from your chat log on Evercold’s release. You might even consider filtering out say chat. Don’t forget to also disable the chat bubbles from these chats. Don’t go on the internet if you don’t want to be spoiled. Going on your XIV-filled Twitter timeline is asking to be spoiled.
Gear:
If you want to use ilvl 790 tome gear for your jobs, you can buy the 780 stuff now. Even if you don’t want to bother upgrading them using the materials from nuts (or Alliance Raid coins) right now, you will be able to upgrade them for Poetics at a much cheaper cost than buying the 790 augmented piece outright for Poetics on launch.
Beast Tribes:
Traditionally, the previous expansion combat beast tribes still give decent XP, at least for the early levels of the new expansion. Do your Pelupelu quests for some easy XP for the alt jobs you want to level quickly, or else the alt jobs that you are not interested in but want to eventually get to max level for whatever achievement reward we get this time. Also, Arkasodara dailies and, to a lesser extent, Pixie dailies will be worth doing to get Bastion and [insert phys ranged here] some easy XP.
Queues:
If you’re trying to do any roulette, be warned that tanks are going to be flooding the queues for the first bit of the expansion, especially the first few days when people are trying to powerlevel Bastion to run the MSQ with it. You will also see plenty of [new phys ranged]s in queue, so if you want to get your roulettes out of the way, playing healer will almost certainly give an instant pop queue, while the other two roles will likely take longer than normal, since very few people are going to be queuing healer for levelling roulette when there’s juicy MSQ to be done.
Previewing New Jobs:
About a month before the release of Evercold (probably early to mid December), SE will invite media to record footage of and showcase the new jobs. All of your favorite (and least favorite) XIV content creators will hastily put together showcases of the new jobs’ rotations. The build they see will actually be a few months older than the current build, so things will be subject to change before the release of the expansion, but this will give you a pretty good idea of what your favorite job will look like in Evercold. For example, this is where we learned that SE has no fucking idea what they’re doing with BLM and WHY WOULD YOU TAKE AWAY ICE PARADOX THAT DOESN’T EVEN MAKE ANY SENSE I SWEAR TO–
Levelling a Crafter:
You will want to level at least one crafter to 110. You will only be able to meld materia yourself if you have one crafter to 110, and Materia Melder NPCs cannot overmeld. You actually don’t need to level your other crafters for repairs: level 100 crafters will be able to repair level 110 gear (at least, that has been the case in the past; currently to repair level 100 gear, you only need to be a level 90 crafter).
Squadron Items:
For some reason, no one wants to hear me say this, but if you just send your squadron out every week, they can come back with some great materials. One of these is the Squadron Battle Manual, which gives a +15% bonus to XP from battle. This does not stack with your FC’s Heat of Battle II (which should be running) which is only a +10%. If you don’t think this is worth it, there are also Squadron Engineering Manuals and Squadron Survival Manuals, which give a +20% XP bonus to crafting and gathering, respectively. Additionally, if you’re going to be doing a lot of crafting or gathering at level 110, Squadron Spiritbonding Manuals can increase the rate at which your gear spiritbonds and will net you some additional crafting or gathering materia, both of which will be in high demand at the start of the expansion. If you’re holding onto +4% XP-boosting food from the previous Twitch drop that came soon after Dawntrail’s release, Squadron Rationing Manuals can make this food last for 45 minutes instead of 30 minutes. Squadron Rationing Manuals can be gotten from your squadron like the other manuals, but they can also be purchased for Wolf Marks.
Other Manuals:
You can also stock up now on Revised Engineering Manuals and Revised Survival Manuals, which can be purchased for Purple Crafter’s and Gatherer’s Scrips (respectively). These give a massive +75% boost to XP from crafting and gathering, respectively, but only up to 2,000,000 XP. This means you’ll want quite a few of them if you want to get all of your crafters and gatherers to 110!
Food:
Boiled Eggs, Orange Juice, literally any food. You can buy some from a housing vendor or from the vendor in the Golden Saucer for less than 10 gil a pop. Always have a food buff going. It’s +3% XP. Is that a lot? No. Is it something? Yes. Eat. Your Warrior of Light is hungry. They haven’t eaten anything but popcorn in months.