VIDEO - How To Make a Safe Lane Change
Rick August of Smart Drive Test explains how to find a safe gap and change lanes properly. Here's the description from YouTube:
The cornerstone of changing lanes safely and properly is to communicate your intention. And remember, "signals are to tell other drivers that you wish to move over, not that you are moving over!"
Too many drivers fail to ask other drivers via their signals to help make a gap for them to merge and change lanes effectively. If other drivers are asked and you give them time to react and respond, most of the time she/he will slow and make a space into which you can merge.
For the purposes of a road test and for safety, you must have 3 flashes on the signal before changing lanes. The purpose of the the 3 signals is:
1) the first signal gets the attention of the other driver;
2) the second signal allows the other driver to locate your vehicle;
3) the other driver takes appropriate action.
In tandem with communication, you have to observe. Before moving your vehicle laterally, ensure that you shoulder (head) check, and after the 3 flashes have completed and immediately before moving the vehicle shoulder check again. And ensure that you leave your signal on until you are completely in the lane into which you are moving.