The single most important piece of academic advice of all has got to be this:
If you don’t love studying what you’re studying,
you ought to start studying what you love!
And if you don’t know what that is, then there can’t be a whole lot that’s more important than finding out.
However.... Supposing philosophy is what you love, there’s no reason not to be a prudent lover, and so we come to what has to be the most important piece of advice specifically for majors and minors in philosophy:
Don’t take too many philosophy courses at once!!!
No one has ever taken five at once and survived, and it’s the rare individual who has taken four at once without stumbling. Philosophy is hard! It takes thought and it takes reflection, and both of those take time.
A word to the wise....