I am not much of a pro-ebayer, but i find that its
best to wait for the last minute.  wish i did it for
the chesta/allen cel thats on ebay.  it skyrocketed to
$355 on the first day cuz i had a very high max.  oh well.
another great cel will always come around.  
there is really no great strategy for ebay.  i've gotten
excellent cels for cheap because no one was really bidding.
just depends who else really wants it and if they have
the money.
^_^
sophie