@Linkat,
Usually, I try to find the source where they are gaining entry and put a trap there, as well as at their gathering point, so they have fast food locations at both ends of their journey, one to capture the interests of those already inside the house, and the other to capture the interests of those newly breaking and entering into the house before they join the others.
Like Osso, though, I find more success by just putting a few temporary peelings of cucumber skins around the location. The cucumbers are said to give off a similar odor as one of their vile enemies and they avoid the place. It works well here.
When I first moved into my apartment, I discovered the ants were using the vacant apartment as a short cut to get from one side of the building to the other, rather than having to walk all the way around it on the outside.
It took two battles with strategically placed cucumber peelings to get rid of them and convince them not to return.