How to hedge against a Fed Funds Rate hike, using futures? You buy or you short the Fed Funds Rate future? Hedge ratio? Other practical recommendations? Over the long term, many years.
You would short FF futures, but proper liquidity in those is only available out to 2y, at the most, if you're lucky. If you want to do further (at most up to 5y) and are confined to futures, you would have to do Eurodollars and run the LIBOR/OIS risk. If you want further still, you will need to do UST futs. Of course, you can do OTC trades, such as OIS swaps, pretty much as far out as you like. Hedge ratio would obviously depend on what it is that you're trying to hedge. The DV01 of a single FF futures contract is $41.67/bp (with the exception of the front contract, where it's variable), so from this you can figure the number of contracts/hedge ratio.