The SEC will notify you that you need to file with the state within 120 days.

Centers of Influence (CPA, Attorney, etc.), referrals from clients, seminars.  Just like the rest of us.

Two suggestions:

1.  Partner up with another independent adviser, either someone with an existing RIA practice or someone who is interested in leaving a wirehouse and go indy.  Obviously, in either scenario, you would have to know the person well enough to feel comfortable doing business with them.  They would also need to have the necessary assets under management to get you over the $25 million threshold. 

2.  Ask your clients if they have any outside assets they would like your input on (401ks, annuities, trusts etc).  Essentially, any signifigant assets that they can’t or don’t want to move to your custodian.  You will want to consult an attorney to confirm this, but it’s my understanding that the SEC will recognize outside assets so long as they are marketable securities and belong to clients with whom you already have an agreement in place.

Good luck.