Hi. For your comfort... Part 1 exams have nothing to do with clinical dentistry. So it doesn't matter whether or not you have been practicing dentistry. Even if you have been practicing dentistry for the past 20 years, Part 1 subjects will require some months of SERIOUS preparations. The truth is this: there is no easy way! (I'm sure you would have worked it out by now!) You will have to sit down and discipline yourself, many people have done so in the past, so why not you? I would advise you to get an old Part 1 exam with answers. Then do it at your pace and time yourself. See how well (or bad) you do. Then work out which areas of Part 1 you are weak. Then prioritize which subjects (or areas) you must cover first. Remember, you should know the basics first! So if you were bad in biochemistry, then start from amino acids and thermodynamics! If you have no clue on anatomy, then get a good anatomy text book and teach yourself! Either that or spend thousands and thousands of money on those private teaching stuff (e.g. Kaplan) but in the end the results will only depend on how much you have learnt.
It's not easy, the entire dental community here knows it! Welcome to the club. Ciao.