Lots of things beside petitions. You can run for office. If you find no parties that share any of your values, form one. You can raise the issue in the media

Lots of things beside petitions. You can run for office. If you find no parties that share any of your values, form one. You can raise the issue in the media which would pressure the government. You would probably not get kidnapped while on vacation in Thailand, and then get locked up without a trial and a forced confession through torture, just for criticizing the UK government. If it's something that affects an entire class of people, such as a certain profession, you could organize something like a labor strike or a protest. And if all else fails, you could actually just break an existing law you think is unfair. You would get an actual trial administered by an independent justice system where you get to defend your actions, you can then argue that the law is unfair and restricted your life in a cruel way. Sadly, it had to come to measures like this for LGBT rights to improve in the UK. You also mentioned "but the people I live around don't". In China it wouldn't matter if everyone around you care about the issue, something will only happen if the CCP deems it necessary.