Everything old is new again.

Is the nostalgia strictly found in the cards, or can an old school environment be cultivated through gameplay and overall atmosphere?

Look at core sets for inspiration
Limit (or exclude) ETB abilities
No Planeswalkers
Limit keyword abilities
Slower pace
Limit Fixing (but make available fixing smooth)

Focus on allied color pairs
Bounce = fastest removal
Auras = next fastest
Instants = most efficient removal, but costly
Slow board wipes down
Avoid easy 2-for-1s that aren't combat tricks