(hindsight) - trading away fetchlands, because they could get me the actual cards I wanted like ebonblade reaper!

Deck building - I was obsessed with black and so mono black was my go to deck. My first deck's mana curve started and ended at 6. I relied on explosive first turn dark rituals to win me games.

first actual strategy - Now that we're talking, I think I'll put this together again! Again, I liked black and i stumbled across zombie trailblazer...

Monoblack Swamp Zombies

4x Zombie trailblazer
4x Buried Alive
2x Entomb
4x Filth
1x Mortal Combat

Various other zombies, but the trailblazer/filth/buried alive-entomb was my engine of doom and it was fun!

I can think of more of what the deck had, but i'm literally finishing this post so I can go play with those cards ;-)