How do you give your friend advice withoust sounding condescending?

my friend always makes excuses for herself about why she does bad in school. I want to say that she should stop making these excuses and that if she tried harder and stopped procrastinating so much she'd do better. Every time i try to though, its like she starts arguing w/ me and i think it's because i sound like I'm accusing her and that i sound arrogant maybe, but i don't know how to say it differently.>.

Tell her if she doesnt want to hear what you have to say about it then to stop whining and complaining to you because youre tired of hearing it. Make a deal to not bring up the subject.