I'd agree with Biff. Initially, you can probably gain from reading a textbook (and substituting with online resources like YouTube and Khan Academy) everything you would from basic courses like Intermediate Accounting I and II. More advanced/specialized courses – Advanced Accounting, Fraud Accounting, Government Accounting, etc. – not everyone takes, so I wouldn't consider necessary (usually they're like “pick 3 from this list of 6”, so not everyone has the same 3). So, I'd start with reviewing a Intermediate Accounting textbook, work through problems, try to understand, etc. If you really struggle with the concepts, maybe consider a private tutor to help out with understanding it, but I'd guess with a decent textbook and some online resources you wouldn't need the tutor. For a “decent textbook”, I'd look for one used in online courses that aren't heavily instructor-reliant. I took my accounting courses through LSU; basically, instructors grade papers, and students learn from the book. I don't remember what Intermediate Accounting book I used, but the prior edition of the book they use now is available on Amazon for $4.20: https://www.amazon.com/Intermediate-Accounting-Donald-E-Kieso/dp/0470587237/ref=sr_1_2?ie=UTF8&qid=1453334556&sr=8-2&keywords=intermediate+accounting+donald+e.+kieso+jerry+j.+weygandt+terry+d.+warfield Given that LSU has picked these authors to use for their students to “self-teach” through the course, I'd guess the book is more readable than some textbooks.
Beyond that, what you need would depend on what exactly it actually is that you're lacking…
Do you lack a basic understanding of the conceptual framework of how accounting works? If so, that's not something that anyone could “diagnose” over a message board, and not something that most professor would put in the time or care to learn. An invested boss might help with that; a good-quality tutor who had real-world experience (not just academic qualifications) could help; but really an old-fashioned mentor is what you'd need…but finding one is hard!
However, more likely, what you lack is simply real-world experience dealing with real-world accounting. I've studied accounting in academics, and I've worked in taxes (granted just for a year), and neither of those really allowed me to understand accounting like working in financial accounting did. Once you see it in real practice, it all starts to make sense. So, if you want to really grasp it, you might just need to work in it. You're not going to be able to step into a Controller role or something like that, cause you still need to get a more solid grasp on concepts yourself before you're steering the ship; however, with tax experience, you wouldn't be stepping into a Controller role, anyway. But if you want to move to private accounting and move to, say, a Staff Accountant, or even a Senior Accountant, go for it! I think most of what you're lacking you can learn on the job.
Unless, like I said in the prior paragraph, you're just lacking something super fundamental. Chances of that aren't too good, but from where I stand, I can't say for sure you're not. If you had someone you could look to as a mentor that could help you honestly assess where you're at, that would be awesome, but finding such a person is often difficult. I'd love to have a mentor, personally, but have never found a way to obtain one. On the flip side, I'd love to mentor someone (when I'm a bit older and wiser and have something to offer 😀 ) but have no clue how to “offer” my services. So, presuming you don't have someone in real life who is in accounting that you can go to for an honest (aka not trying to avoid giving you a raise 😉 ) assessment of your skills, I'd suggest reviewing Intermediate, maybe doing similar with another textbook or two, then trying out a job in financial to see how it fits.
If you're hesitant to make a career jump without getting your feet wet first, see if there's a non-profit you could volunteer with to get your hands in the work without having to move all the way. If you're religious, your church might welcome you as a bookkeeper; for non-religious people, any charity that you're involved with would be a good spot to start, and if you're not involved in any, then you may still be able to put out feelers to potentially get involved. I work at a non-profit college and had someone offer to volunteer in our accounting department the other day, and was thrilled! Still working on logistics, but accountants like cheap, and like free even better…free labor sounds awesome. 😉 haha. Jk…sorta.