If you are worried about other human players figuring out what your ships and planets are being used for based on their names, then I'd suggest coming up with a naming system which is _personally_ meaningful but which would be somewhat cryptic to someone else. For example, in one particular game I've been giving my colony ship classes letter designations; the "Colonizer C" class is for ice planets (after "cryogenic"), the "Colonizer H" class is for gas giants (after "Hydrogen"), and the "Colonizer L" class is for rock ("Lithosphere"). The next time I upgraded my colonizer designs, however, I switched them all around; rock colonizers became "Colonizer G" class (for "ground").
You can even go beyond cryptic and actively mislead a human opponent with names. Give your colonies suffixes like "mil" or "sci" or "stor", but instead of having mil be military bases, sci be science worlds and stor be storage worlds, have sci be the storage worlds, mil be the science worlds, and stor be the military worlds. Of course you'd have to keep track of this; keep notes.
That's the number-one biggest thing. Keep notes. I've got one game which is on turn 120 where I've got a 500KB text file that contains every diplomatic message I've sent or recieved; it's easy to search for the names of systems to find out who promised you what and when. You can also keep notes on a system-by-system basis within the game itself by using the built-in map, but I haven't found that as useful; I keep forgetting to refer to it. Making a habit out of it would probably help, but I think it's just too hard to search them easily.
If one of your neighbors is the Crystal Mentality, don't start producing warships with a class named "Crystal Breaker." Alternately, go ahead and name them "Crystal Breaker" if your _real_ target is actually the Rhodon Network which lies right next to the Crystal Mentality's space (you might want to let the Crystal Mentality know about this ahead of time, though, or it might draw erroneous conclusions). The Rhodon Network's scouts will see them and perhaps start massing its forces along the Crystal Mentality's border in order to scoop up some territory because they think you're going to hit them instead, leaving their border with you wide open.
If you act dumb, a lot of players will assume you _are_ dumb. You can exploit this.
But I digress. Keep notes.