I also want to improve all three of them but I think improving one's speaking skills is not so easy if you don't have anyone to practise with! Thanks to the internet, television, books, cd's and cd Roms there is much choice to practise your listening and writing skills.
Recently I found a good way to practise my listening comprehension; I've downloaded some audio books. (Never thought that this is so much fun
. I've started with children's books cause the language is not too difficult in these books. There are a lot of sites were you can download books for free. You can download the text as well and read along, though I try to avoid that and try to just listen to the spoken language as much as possible.
At the moment I'm listening to "the secret Garden", I feel like a child but I've heard that little children whose parent's read bedstories to them has a wider vocabulary, so I think it's a good thing to do!