Ask HN: Recommended study tools and aids?

It has been over 10 years since I last studied, and I'm returning to studying part time this year, so things have moved on a bit! I will be studying towards a degree, part time over the next few years.

Does anyone have any recommended tools or aids? (Primarily software based, but also interested in any real-world tips)

From learning aids & methods, right through to time management, self testing, and collecting & annotating material - I am interested in any resources or programmes people have found have helped them as a student.

My background the last 10 years is as a developer, and I primarily use OSX, but interested all suggestions.

Many Thanks.