Some thoughts about taking commercial insurance:
1. You can negotiate. Just because they OFFER X amount for a given CPT code, doesn't mean you have to accept it. You need to know your local market to do this best. Know how many psychiatrists are within your city/metro area, identify the largest employers and find out what insurance(s) they offer, etc. Identify any large group practices (w mid-levels) or clinics that take commercial insurance and not, so you know your main competition.
2. Don't sign up for a bunch of insurances, instead do some legwork, call around, talk to colleagues, and figure out which insurers pay better, and start with the best paying AND STILL NEGOTIATE. They will almost always need you more than you need them. They likely will publish out of date "provider" directories, but a little digging will reveal it is full of bad info, retired providers, providers who left years ago, etc. It's a bit more legwork, but if you have the first few weeks "open", take that time and do the legwork because it will pay off when you go to negotiate.
3. Watch out for 3rd party companies that demand a discount up front for X insurance. What do you get for that discount, not a darn thing. Those companies are hired to lower the cost for the primary insurance company, and they keep a % of what they saved the primary insurer. They will often send misleading faxes saying they can get you paid quicker (there is always a disclaimer basically saying J/K!) or other BS. They literally exist to be a leech by slashing your reimbursements and taking a cut for doing nothing but asking for you to lower your rates. Any promise of "added assistance" is BS.
4. Accept that the beginning weeks and months will take awhile. Use that time to scout your competition, get to know the players, etc. If you really want to do it right, identify the top 3-5 largest employers and make a spreadsheet of their insurance offerings. I've actually targeted companies and then gone through their insurer's provider list to identify how many actual providers are part of an insurer's network. I know it sounds tedious, but trust me, it's valuable info. You can outsource the work for $20-$25/hr if you know people.
4b. If you have a BIG employer, you will likely get multiple inquiries in the beginning months from numerous of their employees. Instead of saying you don't take their (primary insurer), encourage them to contact their HR Director to complain about having a hard time finding a provider, and have them use your name as the provider they want to see. If they get a few of these and/or you get the RIGHT people complaining, the HR person can often make demands to the insurance provider about adding to their network. I did this with C-level inquiries a few times before, and literally had the C-level person tell the HR Director to "fix it", and then a senior person at the insurance company was contacting me and bending over backwards to keep the large employer happy. Unless I got 90% of my cash rate or better, I'd only offer a 1 off contract to see the C-level.
The great thing about C-level people is they talk to their peers, and you often can get some nice cash referrals because depending on the size of the company, they may want avoid using insurance to avoid having to disclose anything to their boards about their health/psych status. I know this sounds like a lot of effort, but some of the best connections I made were through working w C-level execs, partners at law firms, directors and dept chairs at same or rival institutions, etc. They have the $ and know the value of a true expert. They tell their friends, and then the friends call you. I've done this with professional athletes and orgs too. I'm not the "official" anything currently (teams often sell the rights to large med practices for $$$), but unofficially and without forking out 5-6 figures to be the "official partner" I see a range of players and sports because I'm trusted.
5. You can do "one off" contracts with insurance companies. You don't sign up for their panel, but you accept 1 patient on a specific agreement. You can test out the company and decide if they are worth engaging with more*.
You can "fill up" in weeks to months being on insurance panels, but unless you negotiated favorable rates, you've already shot yourself in the foot. It's better to get on 1-2 insurance plans at rates that are closer to your cash rate, or at least better than Medicare and better than the average insurer in your area. Don't waste your time with 5-6 panels. 1-2 to start, max.
*I did 1 off contacts for years with a few diff commercial insurance companies as a neuropsych bc they were desperate and I didn't want to be tied down to any more commercial providers. I contracted with two insurance plans (local R1 self-insured plan and BCBS) I'd usually get ~90% of my cash rate and I'd negotiate faster payments with max interest (usually capped by the state/insurance board) after the agreed upon timeframe runs up; this helps w places that like to drag their feet paying. It's a little diff for neuropsych because you get fewer visits but a bigger number, but the idea still works. Always leverage your scarcity and expertise (assuming you look good on paper).
Way longer than intended, but I have a report I'd really rather not write.