What if a Ripple wallet gets hacked? What are the suggested precautions for the average user?
What precautions should be taken to protect a Ripple wallet?
You can keep your wallet offline most of the time. See this. You'll need to go online to check your balance or spend.
Beyond that, I'd also advise you to only use the client while online with that computer.
For Bitcoin, you can keep your wallet airgapped permanently with Armory, but I don't think there's an equivalent solution for Ripple.