Use official taxis or ride apps (e.g. DiDi, Cabify, Uber, ~~Beat~~ (Beat no longer works after 2022)) rather than hailing on the street. Use cabs after dark
Avoid displaying phones/jewelry/cameras openly, especially at night
don't walk around with your phone and your laptop in clear view. Obviously, people will see your a tourist, but its important not to look rich, so dress down. If your a victim of robbery in colombia, the first response will likely be 'what were you doing/wearing?'
Keep photocopies (or photos) of passport and cards separate from the originals
only withdraw money during the day, never after sunset
don't walk around drunk at night
Walk with purpose and look comfortable, but don't be complacent. Walking around looking shit scared is not going to do you any favours and your just more likely to be a target
Travel insurance: research and provider shortlist in
Logistics → Travel insurance — buy before departure; keep policy
PDF + 24/7 assistance number offline (details TBD once purchased)