Once you know the basics, writing them becomes pretty straight-forward.
For a quick crash course: in general start at the top right and work your way horizontally across, horizontal strokes first, vertical strokes after, and then there are some kinds of strokes that always go at the end.
There are lots of little bits that get re-used a lot, and tend to shape the meaning of the kanji, so once you start to remember some of those it gets easier, but is still obviously a large undertaking. :)