This strategy unfortunately will only work as a hunter, but it will be very helpful in the plentitude of quests where you have to kill 10 of this mob, and 18 of this, and 12 of this.
You always end up searching for the one or the other, and although the specific mob might be near, it is not always visible.
What I do now is to create a macro, called Target, and then I change the target item from quest to quest.
Let’s say I need Wild Elekk, then I create a macro by typing /macro in the chatbox, choose New and create a macro with the following text:
/target wild elekk
Drag the icon to a toolbar, and Exit the dialogue box.
Now you can use the macro just by clicking the icon, and whenever the chosen mob is near, and you can see it’s picture on screen, mark it with hunter’s mark and send your pet after it (ctrl+1). Be very careful to follow your pet, and when you are withing range of the mob, use your ranged weapon to bring it down together with your pet.
This trick has saved me a lot of time lately.