a science officer will help you find hidden containers close by, but for the hidden planets....
well to start with try out the beacon quest, it will give you clues on where to find the next beacon, and if you complete it then you'll have access to some of the best hidden systems!
the first beacon is in sector 0,0,0 where you entered the game. i'm guessing you'll have to re-find that one like i did
when your on multi there will probably be someone about who knows where things are. so if you dont mind spoilers then ask away. if you prefer to find em for your self then do the beacon quest.
anyway, general exploring tips. get the biggest fulcrum drive you can, c5 in known space. when heading out into the void put your guns on max energy, aim your ship where you want to go, then keep pressing alt+f2 to jump. re-enter your destination co-ords every now and then to check progress and re-align. also keep the nav map open and zoomed so you can see when you get to your destination. save before you make your final jump, in case you land inside a planet!