A T-account is a visual aid used to depict an account in a general ledger. Above the top portion of the T would be the account title. On the left-side of the base of the T would be any debit amounts; on the right-side would be the credit amounts.
The T-account can be helpful in determining the proper balance for an account or to determine the amount to be entered in order to arrive at a desired balance. I always use two (or more) T-accounts when determining how to adjust an account balance. Drawing two T-accounts reminds us that every transaction or adjustment will have to involve at least two accounts because of double-entry accounting.
A common use of T-accounts is in preparing adjusting entries (accruals and deferrals). I begin by drawing two T-accounts. Next, I note that one of the T-accounts will affect a balance sheet account. The other T-account is noted as affecting an income statement account.
As a young accountant I had to determine the effect of a new FASB standard on my employer's financial statements. I reported on the impact on the company's expenses in great detail. I thought I was done until the controller drew two T-accounts on a piece of paper and said, "What about the other account? You told me about the expense account, but what other account or accounts are affected. You know we have double-entry accounting!"
You might get in the habit of using two T-accounts each time you attempt to determine the proper accounting entry. It will help you see the proper amounts and the proper accounts.