Buy time is running out. This is not financial advice, but the only way to ensure you end up on the right side of the upcoming fork is to have control of the coins before the fork happens. This way you ensure that your coins will be spendable on both forks.
Alternately, you could just sell everything now and wait until one fork wins. There's a chance the price might run away from you before this whole thing resolves, but there's also a chance this whole thing just collapses under the weight of all the in-fighting and bickering.
Hopefully the FUD being spread by the developers (how I love to say that!

) will subside, everybody will upgrade to some big-block version, and the fork will be uneventful, with the old branch dead at birth.
But otherwise that is good advice. If you have coins in an exchange or some other place where you don't have all the private keys, then after the fork you may be able to withdraw only the version of coins that the service owner chose to work with.
One good outcome of the block size FUD campaign is the supply of coinage that will be removed from exchanges pre-fork.