Use a semi-permanent formula the first time around. If you decide you like the shade, wait until it fades and then apply a permanent version.
Back to Front
When dying your hair darker, start in the back not the front. Save the strands around your face for last they tend to be more porous due to daily wear and tear, so they'll absorb more color than the back and underside of your locks.
Look for a permanent shade that has the words neutral, beige, or ash in the name to prevent your hair from looking brassy.
Front to Back
When you're dyeing your tresses lighter, start in the front and work your way to the back so that the pieces around your face are the brightest.
Go to a Professional
Dark brown hair can sometimes turn orange if you lift it more than two levels, so go to a pro if your natural base is darker than a medium brown.
Timing Is Everything
If youre coloring at home, start your timer as soon as you begin applying the formulanot when you finishand don't leave anything on for more than 30 minutes or you'll fry your locks.
Coloring at Home?
Go half-and-half. A dye that's too "warm" might give you an orange hue. For example, if it's golden brown you're after, use one box of golden brown and one box of neutral brown. Mix the two, then use the combo on your hair.