"Can anyone suggest a good book for the TOEFL writing part?"

You can find plenty of information by simply searching for "TOEFL writing part". As well as that, this helpful article below will give you some very good advice.

https://www.italki.com/article/279/five-ways-to-improve-your-english-writing

If your level is upper-intermediate, don't tell us; show us.

yes and my level is upper-inremediate