Almost every residency has an overview video. This can help you learn more information about programs prior to application season. The easiest way to find these videos is by searching "Radiology Residency" + residency name on YouTube.
There is a ton of radiology (and general) application advice on YouTube. These videos are helpful with everything on deciding where to apply, how to complete your ERAS, how to approach interviews, and how to create your rank list.
Most residencies are on twitter. This helps you gain insight to the area, how residents spend their time in and outside of training, and get to know program leaders. It can provide many networking opportunities with students and radiologists. Always be professional.