AGI:
Adjusted Gross Income. This is all of your income received over the course of the year, lumped together. This will include wages, interest, capital gains and dividends without including such things as IRA, alimony payments and other tax exempt monies.
Credits:
Tax credits are credits that you may receive due to your specific situation. For some, there are tax credits for dependants or some business owners may receive a credit.
Deductions:
These are expenses that are approved to be taken off of your tax bill.
Exemption:
You are able to take an exemption for each person that you are responsible for. This is another term for dependants. Depending on how many dependants you have, you can take that many exemptions.
As you move through your tax return, refer to the questions and help for them in your tax booklet. If you simply can not find the help you need there, go to the web for help, or consult your tax professional. At the end of your tax return, all the adding and subtracting will lead you to the amount that you owe to the government or to the amount of a tax refund you are able to claim. Make sure to keep a copy of your tax return for each year for at least ten years time.

Hi, this is a comment.
To get started with moderating, editing, and deleting comments, please visit the Comments screen in the dashboard.
Commenter avatars come from Gravatar.