Change your IP address often if you can.
Do not post your email address.
Do not post personal details which individually can seem innocent enough but when taken as a group identify a specific individual.
Example: Your age, country/state/region, what time zone you are in, whether you are employed or unemployed, your sex, specific knowledge or skills that you obained through education or employment, professional qualifications, whether you have children or not, whether you are married or single, whether your mother can remember WWII or President Eisenhauser, etc etc etc.
Op Sec means thinking about all the ways that your privacy could be invaded and your identity could be discovered by hostile actors. Then doing something about it.