Your statement of purpose is often the only place in your application where an admissions committee hears your voice directly. Transcripts and test scores show what you have done; the statement shows why, and what you plan to do next.
Start with a specific moment, not a mission statement
Avoid opening with a broad claim like "I have always been passionate about engineering." Committees read that sentence, in some form, hundreds of times a season. Instead, open with a concrete moment — a project, a problem you could not solve, a conversation — that shows the interest rather than announcing it.
Connect your past to their programme specifically
Name the modules, labs or faculty that drew you to this particular course. A statement that could be sent to any university, unedited, tells the reader you have not done the research.
Address gaps honestly
If your grades dipped for a term or you changed direction after your first degree, a brief, factual explanation reads as maturity. Leaving it unaddressed reads as something to hide.
Keep it tight
Most programmes ask for 500–1000 words. Write your first draft long, then cut anything that does not answer "why this student, why this course." A counsellor's second read is invaluable here — you are too close to your own story to see what is unclear.