What advice can you give on fishing lake lapeer in summer in michigan?

I am going to my parents house on Lake Lapeer in michigan at the end of the month. It is a small lake in southeast michigan. I am wondering if anyone can give me advice on how to catch a lot of fish. I will have a boat but no fish finder. I have always done well in last spring but never done real well in summertime. Fishing for crappie and anything else that will bite.