I got on my Precinct Committee - YES! I encourage everyone to join in their home towns.
You will need to go through your local town or county Republican Party. Talk to the President or County leader or whoever is in charge. Go to the meeting & find out if there are any open seats (It's called something different in each state eg: Precinct, County Committee, Electoral Districts, etc).
If there is a seat open, express your interest - say you are upset with the state of country & want to get involved to make a difference. DO NOT MENTION Trump, election integrity, etc - until you know it's a safe space. Many local republicans are RINOS & they don't want our type involved! Play the game, play dumb & say you "just want to get involved & make a difference." We have to tread lightly or we won't get these seats.
Once you're in, you have VOTING power - you are in charge of picking the candidates. You will pick who will be the Republican nominees on all levels from your mayor, town council to state assembly, to US Congress to Governor all the way up to POTUS.
DO IT - GET INVOLVED NOW! MAKE A DIFFERENCE!