okay sorry I built the G/W spirits deck because I had a really silly idea
feel free to ignore it, but I really dig this:
Use Tallowisp + whichever spirit/arcane spells you want to grab removal (Faith's Fetters, Arrest, etc) and, when you have a Kami of False Hope available, Gift of Immortality.
Drop Gift of Immortality on your kami of false hope. Congrats -- barring countermagic or removal in response to the enchantment hitting the board, your opponent will never deal damage during their combat step again.
Gift can also hit your other creatures -- it's very capable of protecting tallowisp, etc. Most fun of all, though, is its interaction with Yosei.
Your opponent never gets an untap step as long as you have a sac outlet. If we're staying with old goofy sub-$1 cards, I strongly recommend Freyalise Supplicant.
Bam, G/W spirits is now a lockdown deck.
Preventing early aggressive decks from blowing you out: I recommend upping your more expensive cards (eternal derg, etc) to 4-ofs and running some Shining Shoals. Prevent all damage from one creature, kill another. It really is a sweet card. You can also start running some of the better removal available -- path to exile, etc -- but that isn't fun.
Redundancy -- Instead of something unfun like Worldly Tutor to grab combo pieces, you can just run more. It isn't pretty, but it sure works. Why not run spore frogs and kami of false hope?