As driving instructors we are exposed to the roads and its various conditions 7 days per week. One of the major concerns we see are the courtesies (or lack of) around merging. Below are the rules as stated by Queensland Transport relating to the two different give way rules for merging:

1. On roads where there are lanes marked on the road, if your lane comes to an end, you must give way to traffic already in the lane you are moving to. In the image to the right, Vehicle A (blue) must give way to Vehicle B (green).
2. On roads where there are no lanes marked on the road, when lines of traffic merge, you must give way to any vehicle that is ahead of you. In the image to the right, Vehicle B (green) must give way to Vehicle A (blue). Lines of traffic refer to adjacent rows of vehicles that do not have a lane separation line between them.

1. Merging_with_lines TMR OPTIMIZED

2. Merging_without_lines TMR OPTIMIZED

Often people speed up to race in front of the merging traffic; it should not be a race! Alternately we see so many people that speed up to make it difficult for the merging traffic to enter, it is often difficult for beginner drivers to judge the pace of the traffic that they are entering and can struggle to move across accordingly.
If other road users could remember that they had to learn once too, it would serve to remind them in order to assist novice drivers in many traffic situations as well as the more potentially dangerous act of merging! It is important to use both your mirrors and shoulder checks on approach to your merge, to ensure that cars are not sitting in your blind spot as you are about to merge.
If you are already driving in the lane that merging traffic is about to enter and you have a free lane next to you it is best to move across out of the way to make it easier for them to progress forward. Good old fashion courtesy is the most helpful tool!