Link provided by Duarte Farrajota Ramos is great place to find topology tips (I'm using it by myself) but sometimes you can't find technical aspects of how to create particular topology.
Before I start I want to encourage you to look for good topology without focusing on specific app. Good topology is good, no matter which software was used.
You can achieve it in several ways, I'll show you the quickest one I've found, possible with LoopTools addon (you can find it in User Preferences) wich is shipped with Blender.
- Press W > Subdivide to subdivide a Plane.
- Delete center Vertex.
- Select Edge Loop.
- E to Extrude then S to Scale it.
- W > LoopTools > Circle.
- Add Subdivision Modifier.
- (Optional as needed) Use Bevel or Mean Crease on edges.
In my example I've used Bevel with 3 segments on inner circle edge and corner edges of shape, also I've used Mirror modifier. Everything was made from simple Plane.
Extension (technique without addon):
I've thought that maybe for some reason you don't want to use any addons so here is a method without it.
1-4 steps are the same as in first method.
- Press Alt+M > At Center.
- Press Ctrl+Shift+B to Bevel only Vertex and scale it as needed.
- X > Only Faces to delete central face.