Debit doesn't have anything to do with a debit card, it only means left in Latin! Credit means Right!

When writing journal entries I use 2 simple questions to alleviate any confusion. 

Here are a few examples of this in action:

 

   1. I sold you my MP3 player for $50

            Debit (the left side):  What did I get? 

                  $50 cash 

            Credit (the right side): How did I get it? 

                  I sold my MP3 player 

    2. Purchased Accounting textbook for $160 on account

    3. Paid $700 Rent

    4. Sold math book for $75 on account 

Assets = Liabilities + Stockholder's Equity

English Translation:
Assets are things like Cash, Supplies, Land, Buildings, Equipment, Big shiny metal things, etc.
Liabilities are bills and frequently have the key word "payable". i.e. accounts payable, notes payable, etc.
Stockholder's equity is the net worth of the company. Stockholder's equity normally has something to do with stocks or has the key words "expenses, revenues, or earned."

Note: Every transaction has 2 sides to it, however there does not have to be an increase and a decrease, the transaction may compose of: two increasing accounts, two decreasing accounts, or one account that increases while the other decreases.