Your page is going over because it has more content than will fit on one A4 page. Reduce the amount of content and it will fit.
If you're insistent on controlling exact page layout, I would recommend that you look at a different format for presenting your material. PDF documents are pretty easy to generate and are very precise in their formatting.
You might try letting us in on what it is you're trying to format. There's no generic "make all this stuff fit on a piece of A4" magic bullet. There are possibly ways to make it work in a specific case.