I apologize for the length of this post in advance. It's something I'm passionate about. I'm a shodan with my own club here in Oklahoma. Here's the process I followed and it has been successful so far. I would commend these steps to you.
First, join a national association. I tested for my rank as a USJA member. Since you would be a new member, you can validate your rank with an instructor who is at least a 3rd dan in USJA. The requirements for validation might differ between USJA, USJF, and USA Judo. It might take you a few months or maybe up to a year.
If you can pass a validation test as shodan, then you will have the confidence that comes with knowing your judo meets the standard. When your sensei submits the paperwork for the promotion, you are also required to submit to a background investigation because of the likelihood that you will work with children at some point. This is reassuring to parents.
Next, take the coaching training that comes from a national organization. Before I started my club, I took USJA's coaching clinic and became a certified coach. I also joined the Amateur Athletic Union (AAU) and took their online coaching courses and earned that certification also. AAU's coaching courses are not judo-specific, but they are very good quality. it takes about 24 hours of self-paced training with their certification. I continue to study up on training and coaching through many good sites, like Mark Lonsdale's Judo Training and Development.
One of the beneficial things I've learned is how to manage a club. There's more to it than just teaching judo. I built several spreadsheets that I use to track attendance, promotion points, service points, dates of rank, expirations of USJA memberships, eligibility dates for rank, and other important data. I also set up a separate bank account and I use an online accounting system that allows me to do electronic billing of my students. I keep track of expenses, purchases, facility rental, payments, etc. In the future, as the club grows, I hope to incorporate it as a not-for-profit.
When I started my own club, I registered it with USJA. To become a chartered club with that organization, you have to get five members registered with them. Becoming chartered gives you insurance coverage. Knowing it would probably take awhile to get five USJA members registered, I registered the club and joined the AAU. AAU has the most affordable insurance out there for a new club. Instead of $50 a year, AAU membership was half that price for a year. It was an easier sell for new students and it gave us the liability insurance we needed to get started. This year, we have enough USJA members that we could discontinue the AAU afflilation and just go with USJA.
The nice part about being in the national organization is the support. The folks at the USJA office are very helpful. Every time I've ever called or e-mailed them, they have been great to answer questions, provide guidance, etc. I have guidelines that I can follow for testing my students for rank. There are time-in-grade requirements, promotion points, competition points, and tests for each rank. Having those things helps me develop good lesson plans. I can know exactly what skills and knowledge my students need to have and when they are ready for testing. I don't have to make it all up. They have a good program I can follow and adapt to suit our needs.
When my students test, they can have the assurance that their rank is portable. If they move or if they stop judo for a time, there is documentation they can use to start back where they left off.
Because we are members of a national organization, we can go to camps and tournaments. At a recent tournament, one of my students broke his collarbone. Because we are members of USJA, the tournament director was able to file an injury report. My student's parents can use the supplemental insurance that comes with membership in the organization. They can file a claim and recover the deductibles they paid out that weren't covered by their family health plan. I think USJA insures the member up to $25,000 for such things. Considering the benefit in such a situation, it really makes the $50 membership worthwhile. It also provides me with liability insurance and I can provide a certificate of insurance at no cost to the city recreation center where we practice.
These steps have made our club stable and we are experiencing organic, sustainable growth. I'm in this for the long haul. I hope to see the day when I'll be a white-haired 4th or 5th dan supervising several lower dan-grade instructors leading classes in a dojo owned by the club. I hope to see my current students return with their own children to begin training when they become parents. I'd like to see us be listed on the list of the "top 20" clubs on the USJA web sites. We have a long way to go, but we've laid the foundation for that kind of growth. Being part of a national organization can help us achieve it. I strongly recommend setting your feet on that path so your judo can last a lifetime.