Beginners

Keep yourself educated on the new features and updates.   If you don't know something, ask.  Make sure you are providing your clients with any custom reports or monthly profit and loss as well as open invoices, end of year tasks.  

When I started I has worked for small business, I understood the day to day operational so that I could better assist my clients, many of my clients left previous bookkeepers because they generalized everything and did not help them set up custom chart of accounts, custom reports, did not ask any questions on what transactions are and put things in the wrong place.  Also a lot of Accountants used journal entries incorrectly.  

Biggest challenge is working with client money transfers, loans, cash withdrawals and contributions, making sure those things are not reported as income if they are not, this is another thing I caught new bookkeepers doing, they marked everything deposited as income.  

@L0L1 

Having a solid understanding of debits and credits and the accounting equation (A = L + E) is very important.  When you understand that QB (or any other accounting software) is nothing more than a way to enter debits and credits and keep the accounting equation balanced, you will be able to understand what's happening behind the scenes when you enter a bill, invoice, expense, etc. 

Understand the difference between financial accounting and tax accounting.  Financial accounting is recording transactions to prepare accurate financial statements (income statement, balance sheet, etc.) whereas tax accounting is understanding income and deductions from a tax perspective - they are not the same.  It took me way too long to fully grasp that. 

The field of accounting is vast and has an incredible amount of opportunities.  You can use it in public accounting or private business.  If you're considering getting your CPA license, familiarize yourself with the education requirements in the state you plan to get licensed in because they can vary widely.  If you're detail-oriented (you are if you love math), and have good people skills, you will do well.  Accounting is way cooler and interesting than the "accounting nerd" stigma that goes with it.;-)     

@L0L1  Almost every industry is a customer service industry, and accounting is definitely not an exception.

Don't settle for just understanding an accounting concept well enough to use it; understand it well enough to explain it to a non-accountant, which virtually all of your clients will be.

However tempting it might be to vent about seemingly ignorant clients to your coworkers, resist it, especially if you plan to stay working with a particular firm long-term. Toxic work culture is easy to contribute to and establish, but very difficult to overturn, and often detrimental to the work at hand.

In short, don't forget the human side of the job just because you're dealing with numbers all day. The ability to work well with clients is the difference between the golfer and the caddy.

Also, don't take shortcuts. I've seen many experienced accountants brush seemingly minor discrepancies off, and have spent many hours correcting the fallout from said discrepancies when it all falls apart. Trying to take the easy way out in accounting works out exactly as well as trying to force an answer in a crossword puzzle; it will come out eventually, uglier than ever before. It is rarely ever as simple as 'It's only off by a penny'.