Good writers routinely check their writing - both for clarity and correct mechanics - because every writer misses something or has a writing quirk they need to modify. In the tabs above, you'll find suggestions and practices on how to address common grammar and punctuation errors.
To figure out and master your particular writing challenge, think about the feedback you've already received.
There are also suggestions on how to review your own work under the How To Proofread For Errors tab. Try those techniques to review your papers with fresh eyes so you can see what others see when they read your paper and what you may have been missing.
For questions about citations specifically, see the Formatting & References Guide
For more help, come for tutoring at the AARC!