You can apply for the visa through a travel agency or by yourself.
If applying on your own, you shoukd prepare the following documents:
(I) The original passport with a validity more than six months and at least 2 blank visa pages;
(II) One copy of completed visa application form in Chinese or English (two copies for US citizens), attached with one of the applicant's recent colorful front pictures of upper body (30mm X 40mm)
(III) the certification of the your identity, round-trip (vehicle, ship) ticket or travel check or bank saving statement.