There are two main types:
1. Antithetical parallelism: The thought of the first line is expressed by the antithesis in the second; or is counterbalanced by a contrast in the second.
For example: 'It is easy to send complain but difficult to receive complains.' Or another example is 'And so my fellow Americans, ask not, what your country can do for you. Ask what you can do for your country.'
2. Synonymous parallelism: The thought of the first line is expressed by the same thought or repeatition of the same words in the second line.
For example: 'Our lives were ruined and our existence was destroyed' or 'A man's belly shall be satisfied with the fruit of his mouth; with the increase of his lips he be filled' [Proverbs 18:20]