Learning how to code will both prepare you for actuarial work and set you apart from other applicants competing for similar positions. You can even take learning one step further by creating models (i.e. modeling fantasy sports stats) or simulations (i.e. blackjack hands) to discuss in future interviews, too. Showing you can teach yourself a programming language and apply it to a real life scenario is huge, especially if you can effectively communicate that on your resume and in an interview!
Data vs Computer Memory (data wins)
With that in mind, you can't go wrong in learning intermediate/advanced excel features, VBA, SQL or R during your winter break (or any break!). Below is a list of great resources to help you get started!
The Infinite Actuary Technical Skills Course
222 Excel Keyboard Shortcuts - This is definitely worthy of a hard copy - tons of time saving shortcuts, especially when it comes to selecting and making changes to data.
20 Useful Excel Tricks - There's some overlap from the link above, but these excel tricks can also save a lot of time!
Excel Trick - Really great site with lots of excel advice and step-by-step guides on how to use different features, such as named ranges and other popular features.
Youtube Videos - If you learn better through visuals, I recommend checking out the following two Youtube channels - YourProgrammingNetwork and ExcelVbaIsFun. Both channels have a lot of positive reviews and comments and serve as great resources for learning how to program in VBA.
Guide - If you prefer learning through written guides, this Excel VBA Programming site is a great resource with a lot of different sections to teach you VBA basics.
Course - This free blackboard course is the perfect resource for anyone looking for a more structured course to learn VBA.
Knowing how to code in SQL can definitely help you pick up other programming languages, such as SAS. Unlike VBA, some SQL servers have slightly different syntax (i.e. MySQL vs PostgreSQL), so this is something to keep in mind when you're learning SQL. However, a strong foundation in any given syntax can be easily leveraged across the board.
Guide - W3schools is hands down the best resource for learning SQL. There are a lot of paid courses out there, but this free guide covers everything you need to know to use SQL.
Youtube Video - This hour long video is also a great resource for learning the basics and has a lot of positive feedback.
Guide - This guide can help answer any quick questions you have as you begin coding in R.
Course - This free four-hour course is meant to give you a solid foundation in understanding the basics of R.
Actuarial exams will always be key to landing an actuarial role, but knowing some related technical skills (Excel, VBA, SQL, SAS, R, etc.) can set you apart both as you apply to actuarial positions and once you start work. A lot of processes can be automated thanks to these programming languages, so it will definitely impress your future manager when you can create a new and improved version of an existing process!