Here are some tips for tying knots of any kind:

• Practice. Take a length of fishing line, a hook with the point cut off or buried into a cork, and practice. Practice until you can tie each knot correctly.
• Always wet your knots with saliva as you pull them tight. This prevents damage to the line and allows the knot to pull tight.
• Trim knots closely with a nail clipper. A good knot, pulled tight, will not come loose. Close trimming prevents the knot from catching snags or weeds. Do not burn the tag end—heat damages the line and knot.
• When you're learning knots, the "tag end" (sometimes called the "working end") is the end of the line used to tie the knot. The "standing end" is that part of the line coming from your fishing reel.
• Line is cheap. Always leave a foot or more of the tag end for tying knots so that you can tie them properly.
• Pull up all ends when tightening the knot. With some knots this will be only the standing end and tag end; with other knots it might be three or four ends.
• Once you find a rig that's working (a combination of weights, hooks, swivels or floats used for a particular type of fishing) don't lose it. 
• Replace the line and retie your rigs at least every year.

Your First Knot: The Arbor Knot

The Arbor Knot is used to tie new line to the reel. It's the first knot you need to learn. It doesn't have to be that strong. And it's easy to learn. That makes it a pretty good knot to start off with.

Run the line around the spool hub (arbor), then take the tag end around the standing part of the line and tie an ordinary, everyday, overhand knot. Tie a second overhand knot in the tag end as close as possible to the first one. Pull on the standing part of the line and jam the two knots together against the spool of your reel.