With the similarities paragraph, it is necessary to begin with differences. For instance, if I'm writing about how Brazil and the United States are similar, I would start with something along the lines of:
While people in Brazil and the United States eat different foods, speak different languages and enjoy distinct cultures, there are several fundamental similarities between the two nations"
You would then list the similarities:
* Both are huge with multiple time zones and climates
* Both have a history of slavery and a multi-ethnic populations
* Both regard personal independence as essential
List the similarities from the least important to the most important.
Also, remember to reduce your reasons to just one key word if possible.