When she is complaining about work or life, don’t try to provide solutions. That’s not why she is talking to you. Be caring and supportive. Guys usually are in a problems solving mindset and think they’re helpful but If you try to just toss around opinions or suggestions about every problem she has, she will think that you don’t have any respect for her intelligence or abilities.
Just appreciate her and show it too. A lot of relationships could a lot stronger if people didn't think that hiding their appreciation makes them look stronger or more independent.