Please advise how to see a psychiatrist without a referral from a gp?

Contact local clinic. Though often your gp who knows you is a good source of referral to specialists such as psychiatrists other sources include local clinics. Insurance panels, local medical societies, nearly medical center. Some but not all insurance plans require a referral from your gp so double check and good luck.
Psychiatric eval. Many psychiatrists don't require referrals. What does your insurance company require?