1. First, have a look at these slides if you have not yet seen them, http://cs.au.dk/~mgreve/algocomp/acm_slides_2009.pdf.
2. Start doing the USACO training program, http://train.usaco.org/usacogate. This is the only training program that exists. If you are already somewhat good at this stuff, it may be quite boring. The first few problems are definitely boring. Nonetheless, it is a good idea to go through it.
3. Register at the TJU online judge (http://acm.tju.edu.cn/toj/), and start solving the following problems. Note that the order given is not necessarily the best order to solve the problems. We did these problems during the session. Most of them are quite hard except perhaps the first. I would expect most to need a lot of hints to solve them.
Printer Queue, NWERC 2006, http://acm.tju.edu.cn/toj/showp2647.html.
Pie, NWERC 2006, http://acm.tju.edu.cn/toj/showp2644.html.
Escape from Enemy Territory, NWERC 2007, http://acm.tju.edu.cn/toj/showp3033.html.
Prime Path, NWERC 2006, http://acm.tju.edu.cn/toj/showp2648.html.
Card Game Cheater, NWERC 2005, http://acm.tju.edu.cn/toj/showp1511.html.
A Number Game, NWERC 2003, http://acm.tju.edu.cn/toj/showp1506.html.