I would recommend waiting for the 30 months and ensuring that you have full documentation. While you can get by with a statement by a mechanic or inspector with whom you've worked, I would do more. Compile a list of all the aircraft you've worked on (as best you're able) by N number and type. Compile a list of all the maintenance operations you've done, listing each thing to show a complete break down of your experience.
This, along with an affadavit by a supervising mechanic, can be turned in when you want your authorizations to take the knowledge (written) exams. You'll have three exams; the general, airframe, and powerplant. Then an oral exam, and a practical test. The test is usually longer than what you're accustomed to; they typically last one or two days, and aren't generally less than about eight hours long.
One drawback to doing it based on experience is that you sometimes don't end up with experience or knowledge on many of the areas to be tested. You'll be expected to be able to do anything that someone coming out of a maintenance school could do, so be prepared. This will include searching aircraft records, performing maintenance entries, a thorough understanding of aircraft paperwork including AD's, histories, aircraft specifications and type certificate dats sheets, etc. You'll need to understand brakes, timing mags, riveting (including being prepared to answer standard questions about rivet and edge spacing, sizes, drill sizes, etc), hydraulics, propeller balancing, and every other aspect of performing maintenance such that you can answer questions on each subject and then demonstrate ability while doing it.
You'll only be tested on a certain few items, however. When you go to the prep courses, they'll usually have you concentrate strictly on the things they know the examiner will be asking about. In my case, I did it on my own, and didn't know what the examiner might ask, so I spent a year of concentrated study preparing for the test. I had an eight hour oral exam, and then had to demonstrate timing mags, researching AD's, making maintenance entries, riviting, balancing a prop, inspecting an aircraft (eg, 100 hour inspection) for certain requested items, and so forth.
I believe it's ASA that puts out the study guides by Dale Crane. They're excellent prep materials, and are formatted like the written study guides that you're used to seeing. They also include oral exam study guides in the back, and an additional oral exam study guide is available to prepare. It seemed to me that many of the questions actually asked during the oral portion of my exam were from that study guide.
Interestingly, when I was taking the test, the examiner walked me through a warehouse filled with various parts, components, structures, etc. Part of the exam included identification of components and parts, and answering questions about them. Many were parts I had only read about, and had never seen. He told me then that it might be the last and only time I'd see them.
As it turned out, within two weeks of completing the exam, I was working on all the things he said I'd never see; large radial engines, expander tube brakes, etc. I was performing functions he commented I'd probably never perform, like fabricating hose assemblies and doing large scale heavy maintenance at the depot level. At the time I took the test, I thought it wouldn't be much more than something on a resume. However, I took it very seriously, and was prepared, and as it turned out, it's been heavily used ever since.
If you don't own them now, start purchasing tools. Get decent ones, even if you have to buy only a few over a long period of time. Don't get cheap tools, no matter what your budget or how great your temptation. A word of caution; MAC and Snapon are industry standards, and have always been popular because where ever you go you can find a truck, they come around weekly, and replace what breaks without reservation.
MAC has had a change of policy with their drivers in which it's largely up to the individual driver as to weather he or she will warranty your part. That can be a problem. I don't know that Snapon is the same...but get to know your local dealer and don't go with brand preference. Also, if you're starting out, don't get suckered into a brand name box...I've seen many guys get stuck into a twenty five thousand dollar tool box and soon find that their wages in the long term won't support it. I've seen divorces result over a box.
Craftsman makes as good as any (in truth, the same people that make Craftsman boxes make most of the boxes on the market); get one of their better boxes (rollaways), and it will be considerably less expensive than a Mac or Snapon.
Concentrate on the basics for now; a good setof screwdrivers, combination wrenches, 1/4" drive sockets and extentions, and a plier assortment to include duck bills, a good set of dikes, and several different needlenose pliers. Get a small set of ball pean hammer and soft-tip (rubber face) mallets. Add to these things as you can, one step at a time. Stubby wrenches are important. Flex sockets can be a life saver. Carry basic sheet metal tools; eventually you're going to want to build a bucking bar collection, some rivet guns, various rivet sets, etc. A compression tester, filter cutter, etc, will be used a lot. A timing light will get used a bunch.
I buy a lot of craftsman tools; they have a lifetime guarantee, and they're good tools for the most part. I also buy off the trucks, and mix and match my tools. Whatever you do, get decent tools, because you're livliehood depends on them. Get a decent pair of safety wire pliers; you're miles ahead to get a reversible shorty pair (the six inch); you'll be glad you did. Milbar or Robinson.
Get a decent multi meter. You can get some good ones from Sears. Don't buy Sears torque wrenches.
I hope some of that helps. Good luck.