Make an outline of the points you want to talk about. Write as much as you can without regard to transitions, but make sure you separate different points into different paragraph. Then, the transitions can become easier since you already have material you're working with.
Some words that can be used to link your sentences are as sandrie mentioned "similarly" or "in contrast", but you can also use "later on", "then", "furthermore", while in the movie [does this], the book [does this], etc.
Ask a friend to read your paper for help with transitions or to proofread your paper. Most colleges also usually also have a writing center where you can request help with writing assignments.