Honestly I think it's best to learn from Death and His/Her aspects Themselves. My choice of spirits are Hela and Samael. Samael's good for everything from psychopomp work to communing with ancestors to crossing the hedge to Hell to aiding spirits to cross over and honestly, just giving you a healthy appreciation of life and becoming dirt and worm food once you die. Hela's more for seidhr for me and the mystical aspects of death, death is a great way to reveal the truth of things, for what is more honest than rot, decay, and fructifying the soil with your own starstuff corpus? I would say, romance death, flirt with death, fucking realize you are dying every moment and then you can begin to truly live.
A great ritual Hela taught me to invoke the dead for wealth and protection is take a match box, go to a graveyard at the new moon, put two pennies, old copper smelling like blood ones, a tarnished dime, fill that shit up with graveyard dirt, invoke the ancestors, and bury the box at a headstone of your choosing.
Also meditate on the Hebrew Tawu. To me, that is the key to Samael's mysteries, and hence Qayin's, as he bears the tawu mark. In Heathenry, we call it Gebo, a gift for a gift. It is death, and in death, life. Also gnosis of the self and hence your own godhood.