Hello studnet,

Some of the tips or tricks you should follow in order to get 500+ score im MUOET are as follow:

• Go for ncert text books for basic concept as ncert is like a god of this exam. Most of the time a few question directly comes from ncert books.
• Don't answer a question for which you are unsure. As there is negative marking in this exam.
• Toy should go for English first as it is a scoring subject for this exam and will help you to lift your score up.
• Try mock test as much as possible and improve your accuracy and speed of attempting  the question.

Hope it helps. 

Thank you :)