How to easily make mesh retopology? After creating some hi-poly model, i'm always creating low-poly model by approximating that hi-poly mesh with triangle-by-triangle LP mesh - with snap to face mode turned on. 

So the process looks like CTRL + RMB (x times), and hitting F on keyboard, so the new face was made.

Then I'm using this low poly model to texture baking, mainly for gamedev purposes.

This method is very time consuming, so how to make retopology process easier and quicker?
Here are some wonderful tools for speeding up the retopology process:


polystrips (https://www.youtube.com/watch?v=VN1aC7DsS6A)
contours (https://www.youtube.com/watch?v=5RR06wjt2rs)


These are paid, but worth every penny as they're really time-saving tools.

If you don't want to buy them you may do a fast retopology using a Bsurfaces addon. Go to User Preferences (Ctrl+Alt+U-->Add-ons) and enable it.


Add an object you want to retopologize, then add a Plane (or any other object you like), enter the Edit Mode and delete it (x). In the Properties Panel (N) add a new Grease Pencil layer, then go to the Tool Shelf (T)-->Grease Pencil and change a stroke placement to Surface.


Now go to the Tool bookmark in a Tool Shelf. Draw some strokes on an object (hold D, then press LMB [ How to draw grease pencil on a surface (blender 2,75)? ]). When finished, click on Add Surface in Bsurface panel. Change the settings below as you like.