This may be a good choice for someone who (like yourself) is already superficially acquainted with some of the definitions and methods of Diophantine geometry:
The following two are great expository articles (especially the first), which provided me with plenty of inspiration back in the day:
Henri Darmon has a couple of nice articles on the topic of rational points on curves:
Anthony Varilly-Alvarado has a number of very good introductions to the topic of rational points on different types of surfaces:
Alexei Skorobogatov taught a course in 2013 on the topic of rational points on surfaces and higher-dimensional varieties. The notes strike a great balance between accessibility and generality:
- Arithmetic geometry: rational points (link)
Then there are these notes by Yonatan Harpaz on rational points on elliptic surfaces:
- Rational points on elliptic fibrations -- Course notes (link)
Finally (for now), Brendan Hassett has a nice article on the topic of potential density of rational points on varieties, which is very interesting as well:
- Potential density of rational points on
algebraic varieties (link)