Open the box carefully. Though this step seems obvious on its face, it is often the first place that things go wrong. More often than not, your furniture will come in a cardboard box, sealed with packaging tape. To cut the tape, opt for a pair of scissors rather than a knife or box-cutter. You don't want to stab through an IKEA box only to find that you've permanently scratched your new furniture.
Arrange all of the small components first. Separate each type of nut, bolt, tool and screw into its own cup or bowl. Often times IKEA will provide multiple sizes of the same small piece. For example, there may be three sizes of screws but IKEA's directions don't always make it abundantly clear which one to use for the job at hand. The best way to avoid confusion is to separate out these small items and take the extra time to label each bowl with the part's identifying number from the IKEA instruction manual.
Check the box before moving it out of the way. Sometimes IKEA instructions can be as brief as one page and can often get lost or stuck to the side of a cardboard box. Make sure the box is empty before putting it aside.
Assemble in a well-lit area. It is often difficult to see small holes in the furniture so be sure to have adequate light for the job.
Use real tools for the job, when needed. Though most IKEA projects can be done with a simple Phillips head screwdriver and the IKEA tools provided, it is often done quicker and better by using tools you may already own. The most useful tools for putting together IKEA furniture are a ratchet screwdriver and a ratchet wrench. These tools allow you to tighten bolts and screws without having to struggle with flimsy wrenches or have to reset your grip each time.
Keep a close eye on which piece is being used in IKEA's instructions. It is often difficult to tell which piece you will need for the step. Look at the number and position of the holes in the diagram; this is often the best indicator of which piece you need. Also keep in mind which side of the furniture is going to be seen. When you see an unpainted part of the wood, that usually indicates that it will not be seen; it may be the underside of the furniture.
Retrace your steps if you hit a snag. Despite your best efforts, you might still put something on backwards.