There are many Sith tecniques, there are lightsaber tecniques, force combo tecniques, and medatating tecniques.
Light saber techniquesSith often use quick overwelming tecniques to quickly and effeciantly do the job. Other saber techniques enabel extreme anger two use multiple power strikes then a suprise sweep or stab. A dual saber technique is to keep your enemys on eather side then alternate between attacking the front and defending the back and attacking the back and defending the front. Count Dooku uses form 2, Makashi, while modifing it with anger. Out of the seven forms of lightsaber combat, a sith usually prefers form four- Ataru, form five Shien/ Djem so and/or form seven Juyo for their mainly offensive focus.
Again, there are many force combos. My personal favourite is when you fuse your lightsaber with force lightning causing you to inflict extra damage and stun enemy without direct contact with your saber. Other force combos include lots of saber throws, engaging enemies in a saber lock then using a force push and using techniques in the lightsaber section
Many sith medatation techniques involve getting better at your powers and healing your self. Darth Plagius uses Sith medatation to alter life itself.