Well, of course bootmii/boot2 is the best brick protection possible, but this is not an option for you. Priiloader provides decent brick protection, but not against full bricks. So as long as you don't mess with either the system menu or the system menu IOS, priiloader will protect you. It's also wise to check whether you disabled updates. Updating from Nintendo can be dangerous in some situations.
Aside from priiloader, the softmod any wii guide also offers some brick protection. It makes it harder for Nintendo to update and prevents Nintendo from stubbing certain IOS'. It is also able to prevent some upgrade/downgrade bricks, as well as error #003. It also provides some extra brick recovery options using savemiifrii.
Another great way to recover you wii from a brick is a NAND back-up. It may not protect you from a brick, but will enable you to restore it.