I'm also getting ready to start competing next year, probably in Men's Physique. I have been working out with a trainer 2-3 times per week for 6 months and it has completely changed the way I approach my workouts. I highly recommend it. It's expensive, but if you're going to go down this road, you have to make the investment. Equally as important, and perhaps even more, is diet. I was very lucky to have had a nutritionist do my diet for the first month, and I got to see how he calculated and adjusted calorie intake and macronutrient breakdown. From there, I did a ton of self-study and I do my own diet. If you are willing to spend some time on self-education, you can do your diet yourself for the most part. I do plan to hire someone to do my pre-contest diet, however, as there are lots of methods for reducing water bloat and getting insanely cut that I don't really know about yet.
So yes, spend some money on a trainer, one who is a bodybuilder him/herself or who has trained bodybuilders. And yes, get someone to do your initial diet. And read everything you can about nutrition.
The only other thing I would say is to set and track your goals, both short and long term. I sat down with my trainer and took measurements and body fat a couple weeks ago because my new goals are to bulk to 200, add an inch to my arms, see noticeable calf development and get my forearms proportionate to my upper arms by the end of the year. It's a huge help having someone to help track things and motivate me.