Talk fast (literally)
If there's a stargate, there is a good chance that there is a civilisation also. An Earth year gives you time to explore before you return and set up camp next to the stargate.
Find the locals and make friends with them. Any civilisation will have its own means of time keeping so your priority is to synchronise your time with theirs. Then perform the necessary conversion and allow a good margin for error.
As others have pointed out, you have only your body to rely on and most bodily functions are variable in periodicity. Therefore you need to know a constant.
Solution
You need to prepare before your travels but that's only sensible for any gate traveller.
Learn a long piece of poetry or a passage of Shakespeare. You must learn it perfectly and be able to recite it without stumbles.
Practice it many times getting faster and faster. Keep a graph of your progress. When your speed of recitation has peaked, measure the overall time that it takes.
Fine tune the length of the text to last a time period you choose, for example an hour. You don't have to do this but it just makes later calculations easier.
You now have a constant that depends only on the physical constraints of your vocal apparatus. Maintain speed by practicing every day at full speed and time yourself.
Work out the mean error. People who go for world record speaking contests get down to a remarkably constant rate so the error is likely to be 'small'. (Note: I say this from memory from an interview I heard a few years back. It would need research to back it up but I'm pretty certain it's true. The same applies for athletes, they tend to peak at a fairly constant level.)
Now and only now are you ready to journey to other places.
- If you are alone on the planet, you have a PGTC (pretty good time constant). You must synchronise with local astronomical or other regular events. If there is a friendly civilisation, you can synchronise with their time system and from then on rely on their time-keeping. Allow a generous amount of time for error and then spend the intervening time building relationships and supplies to prepare you for the time you decided to encamp next to the gate.