Revision is an essential part of studying any subject, especially when it comes to important concepts and theories in mechanical engineering optional subject. Here are some effective ways to revise these concepts and theories:

1. Understand the Syllabus:
- Familiarize yourself with the syllabus and identify the important topics and subtopics that need to be revised.
- Categorize the concepts and theories based on their level of importance and difficulty.

2. Create a Study Schedule:
- Plan a study schedule that allows you to allocate sufficient time to revise each topic.
- Break down your study sessions into smaller, manageable chunks to avoid feeling overwhelmed.
- Ensure that you include regular breaks to maintain focus and prevent burnout.

3. Review Lecture Notes and Class Materials:
- Go through your lecture notes, textbooks, and class materials to refresh your memory on the concepts and theories.
- Highlight or underline important points and make short summaries to aid in understanding and retention.

4. Use Visual Aids and Diagrams:
- Utilize visual aids such as flowcharts, diagrams, and concept maps to represent complex ideas visually.
- Visuals can help in better understanding and recalling information during the revision process.

5. Solve Practice Problems:
- Practice solving a variety of problems related to the important concepts and theories.
- This will help you apply the knowledge gained and identify any areas where you need further clarification.

6. Form Study Groups:
- Collaborate with classmates or join study groups to discuss and revise the subject together.
- Engaging in discussions can enhance understanding, clarify doubts, and reinforce learning.

7. Utilize Online Resources:
- Make use of online platforms like EduRev, which provide a wide range of study materials, question banks, and video lectures specifically for mechanical engineering optional subjects.
- EduRev offers a comprehensive collection of resources that can aid in revision.

8. Take Mock Tests:
- Attempting mock tests and previous year question papers can help you assess your understanding of the subject.
- Analyze your performance, identify areas of improvement, and revise accordingly.

9. Teach Someone Else:
- The best way to consolidate your understanding of a concept is by teaching it to someone else.
- Explaining concepts and theories to others can help you identify any gaps in your knowledge and reinforce your understanding.

10. Stay Organized and Consistent:
- Maintain an organized study environment to minimize distractions and maximize productivity.
- Be consistent with your revision schedule to ensure regular and effective studying.

Remember, revision is an ongoing process, and it is crucial to allocate sufficient time for it. By following these strategies and incorporating them into your study routine, you can effectively revise the important concepts and theories in mechanical engineering optional subject.