Warding - a request, Oh the irony Options

Yes, it's somewhat amusing that I'm asking for help - but does anyone know how to set up anti-spirit wards?

I have a twofold problem. Firstly, I have a whole load of "othersiders" who are attempting to get my attention (for some indecypherable reason), and I'd rather like them not to enter my room, and secondly, I need to be able to set up wards without arousing the suspicion of my parents.

So, here's my request:
Does anyone know how to set up strong physical wards, without them being too obvious? They'd need to be broad enough to block out everything of a non-physical origin.

I've had my room psychicly "cleaned" (which was nice at the time) and I've had it shielded with a basic version of the technique you've described.

Problem is, I'm dealing with an innumerable amount and of no set aspect. Last night, for instance, I had a shade (effectively, a 6ft tall shadow) who'd managed to work up enough power to open doors, I've previously had anything from spectres (as in, a dead person who just stands there looking dead) to just random things that defy any specific naming.

Would be nice though, if they didn't enter my room, which is why I'm asking.