Visiting Florida in February

My husband and I are planning a trip to Florida next month for the first time. We'll be there for a week and have a rental car; flying into Miami 2/13 and out of Orlando 2/20. I was thinking we'd spend the weekend in Miami, see the everglades, then go up to Crystal River to see manatees. Any recommendations or advice? Things to see, places to stop, restaurants, things to avoid, better places to see manatees, etc.