It's always annoying to walk through a Stargate and come out somewhere random, far away from any visible Stargate. Sort of breaks the mood, you know?
Please, as a courtesy to other Stargate travelers, do not place your Stargates on land with restricted access ("about land" / "access" should not have any check boxes selected), or with a teleport routing away from the Stargate ("about land" / "options" / "teleport routing" should say "anywhere"). Alternately, you can set "teleport routing" to "landing point", and place the Stargate at the landing point. If you wish to have a seperate landing point from the Stargate, you might consider splitting off the 4x4 m^2 section containing the Stargate ("edit terrain", "subdivide").
Also, if placing your Stargate in a private region, make sure region permissions are set to allow people to teleport to the region.