Recommendations and advice to further my RF career

Hello everyone,

I was wondering if I could get some advice/recommendations on what to learn/read to become an RF design engineer. I was currently given an opportunity to work in a test group working with RF devices. As this is my first time working in RF. I believe testing these devices will help me learn more about RF but was hoping I could get some guidance on things I should consider or think about while working in this group to help me move onto designing. Thanks in advance!