Basically you load up on your favorite High CMC spells - Eldrazi Titans (Ulamog, the Infinite Gyre), extravagant board wipes (Decree of Annihilation), whatever you find interesting (Myojin of Night's Reach) and just go to town
These apps can make pricing your entire collection a breeze
The Recs page takes your decklist and produces customized recommendations based on comparisons to similar deck lists
Finally, Prismatic Geoscope is a super-powerful mana rock, and while entering the battlefield tapped is annoying, going from five mana one turn to 11 mana the next has the potential to do some broken things
Just beware of graveyard hate
In grind-heavy Commander games, each death shifts life totals in your favor, and over multiple turns, that pressure becomes impossible to ignore