At this threshold, your focus should be on grinding out your Shining Crescent and Titansbane Skill Advancements as well as practicing your burns.
Godsfall
This is the basic Godsfall. This should allow you to get 8 Shining Crescents off and the third cast of Twilight Waltz if you have buffs. The final cast of Twilight Waltz might be difficult to squeeze in. I recommend using Shining Crescent immediately at 7 runemarks and off cooldown (i.e. Ground Bash isn't worth losing the Shining Crescent or Twilight Waltz at the end). While this rotation is easier than the one that will follow, keep in mind that it is still pretty tight.
Note: The Shining Crescents in the GREEN BOXES may still be on cooldown if you have excess speed so I strongly recommend using filler to keep this rotation as fluid as possible. If -for whatever reason- Godsfall has less than 3-4 seconds left when you get to the RED LINE between Shining Crescent and Twilight Waltz, you should wait for Shining Crescent to come off cooldown naturally (which would most likely be after Godsfall ends) before using second Twilight Waltz reset (unless Twilight Waltz is going to go on cooldown or the fight is going to end very soon).
Basic Godsfall Rotation:
Ragnarok
This is the basic skeleton of our Ragnarok rotation. You want to hit 4 Shining Crescents within Ragnarok and so that means you need to hit Shining Crescent off cooldown. The best way to ensure that you do this is that as soon as you see Shining Crescent hit a 3 second cooldown mark, go ahead and Runeburst > Maelstrom > Gungnir's Bite and you should meet your Shining Crescent as soon as it goes off cooldown.
TL:DR:
Less speed = Less skills cast for Runeburst rotation so you need to be efficient with Runemark stacking
More speed = More freedom to cast more skills and ability to overcap Runemarks
Both scenarios still want to initiate Runeburst at 3 second mark on Shining Crescent.
Basic Ragnarok rotation:
Additionally, you may want to start learning how to Twilight Waltz in Ragnarok; however, there is a common misconception in the valkyrie community that you pretty much always want to Twilight Waltz off cooldown or in Ragnarok. This is simply not the case and where valkyrie begins to show an apparent difference in player knowledge and skill level. To correctly use Twilight Waltz it has to fit certain criteria. This could be:
Optimal Ragnarok Rotation with Twilight Waltz:
Build Phase
The final thing you need to focus on is building Ragnarok. Info dump: