What I have found most useful is a phrase book that contains english and pinyin and characters, all aligned together (this was in the Lonely Planet books last time I went to China, don't know about currently). You can look up the english, then point to the character whilst trying to pronounce the pinyin. I found this to be a great way to both communicate and to make friends as the locals would laugh at me/try to help me with my frighteningly hideous pronounciation.

And always keep a stash of your hotel's business cards with you - all the ones I ever stayed in had english, mandarin and a map.

Cabs are incredibly cheap, IME.