The IRS has a huge collection of useful and (well, if you're like me) interesting tax tips about all sorts of tax-related issues. Here's the link:
And a couple of tips of particular interest:
Errors to Avoid at Tax Time (such as missing SSNs, math errors, etc)
Nine Things You Should Know About Penalties (ie. paying late, failure to file, etc)
Standard or Itemized Deductions (really good stuff to know)
Additional Standard Deduction for Real Estate Taxes (until recently, if you took the standard deduction, you couldn't deduct your property taxes. Now, even if you take the standard deduction, you may get to deduct up to $500 or $1000)
Top Ten Facts About the Child and Dependent Care Credit
Lots of good stuff there and well worth taking some time to poke around. All of these short articles include links to more detailed reference material, usually various IRS publications such as these:
IRS Pub 17 (Your Federal Income Tax)
IRS Pub 503 (Child and Dependent Care Expenses)
IRS Pub 590 (Individual Retirement Arrangements - IRAs)