The first tier set of Dragonflight for Elemental is quite good:
- 2 Set: Lightning Bolt, Chain Lightning and Lava Burst increases the damage of your next Earth Shock, Elemental Blast or Earthquake by 5%, stacking up to 5 times.
- 4 Set: Casting Earth Shock, Elemental Blast or Earthquake increases your mastery by 8% for 5 seconds.
The 2 Set is pretty good because overloads also generate stacks meaning that you will most of the time have a 20-25% damage increase to your maelstrom spenders.
The 4 Set is weaker but still pretty solid providing 8% mastery with upwards of 70% uptime which most of the builds scale very well from.
For embellishments, there are a very limited number of options.
One of your two embellishments should be the Elemental Lariat. The buff it gives has about a 35% uptime of a big mastery buff.
The second one is a bit more gear dependent.