Paid advertising on social media, particularly Twitter, Facebook and LinkedIn can be highly targeted and so I am sure you could find relevant keywords and topics to target using those platforms.

Depending on where you are in the world, look for events on meetup.com and/or Yelp. There are almost certainly going to be groups and events related to your target demographic. Think book clubs, wine clubs, sports, theatre etc.

Digital signposting - e.g. screens at medical establishments, local public transport, gas stations.

Lastly, perhaps advertise at night-schools or venues that host a lot of evening classes.