How should I diversify my 401k?

As a 30 year old why do you want to be so conservative? Try looking into some ETF's that are clified as aggressive that might be able to grow your portfolio rather than just maintain it at or below the level of inflation. I would recommend talking to a local financial adviser that charges a percentage of the ets under management. It is in there best interest to give you the best portfolio possible (the more money you make in your portfolio, the more money they make)