If we understand the wormhole as a black hole/white hole pair (a Schwarzschild wormhole), there is no way to know if it is a wormhole before entering. As far as the observer outside the entrance knows, it is a black hole... and then the question is what preparations are needed to survive entering a black hole?
For that, see No Way Back: Maximizing survival time below the Schwarzschild
Instead, I'll assume that we are talking about a "traversable wormholes" (Lorentzian Wormholes). In this case what is needed is whatever is needed to survive in outer space for a reasonable span of time.
These wormholes can be used both ways, as they don't have any special direction. Furthermore, there is no reason to believe that the wormhole is a violation of the principles of universality - that is: "all laws of nature must work the same way everywhere" - and locality - that is: "an object is only directly influenced by its immediate surroundings".
Therefore, you should be able to see to the other side of the wormhole, in fact, any radiation would be able to travel from one side of the wormhole to other, allowing the travelers to prepare to whatever is on the other side.
-- Image of a simulated traversable wormhole that connects the square in front of the physical institutes of University of Tübingen. More Information.
It is expected that the wormhole has an equivalent gravitational field due to its curvature (take your artistic license on that), in which case it is gravitationally attractive from both sides... you would need a ship able to reach the scape velocity of the wormhole. Note that these gravitational field depends on the curvature of the wormhole.
Aside from that, because of the principles mentioned above there shouldn't be a place during the journey where you suddenly experience or stop experiencing a gravitational field... which implies that gravitational fields can affect to the other side of the wormhole. So, for example it makes sense that a wormhole with one end nearby a planet and another in outer space would be attractive on the outer space end in proportion to the gravitational force exerted by planet on the other end.