A friend and former colleague tried to get hired where I work, but he didn’t tell me or ask me for help or advice. He’s more qualified to work where I work as he taught me most of what I know about design. We talked after he was rejected. I looked at his portfolio and I asked him questions about the process. In both the answers and in his portfolio I could see opportunities where I could have helped guide him so that those who interviewed him would see what I know of him.
Never do it alone if you don’t need to. There’s no shame in asking for help.