Blender 3D: Noob to Pro/Modeling tips

This is not really a tutorial, but a list of handy tricks you will probably use a lot when modeling.

1: Extrusion: To extrude, press  E  in edit mode with the vertices selected, move and click to place the extrusion. You'll basically need this for every model in blender, without it, most models would be really hard to create.

2: Set Smooth: Enabling smoothing on the face of a mesh will create a smooth gradient between it and the faces around it. To enable smooth shading on a face, select the faces you want to smooth and then go to Mesh → Shading → Smooth Faces.

3: Merge by Distance: Sometimes when editing, you might accidentally create duplicate geometry or have small holes in your model. To clean these up, select your entire model (or part of it) and then go to Mesh → Clean Up → Merge by Distance. The Merge Distance variable when performing this action determines the maximum distance between vertices for them to be merged.

4: Topology Flow: One of the most important things to keep in mind while modeling is the topology of the model. Topology is the arrangement and flow of the edges and faces that make up a mesh. Generally, you want to make your model with quads (faces with four edges) so that it is easy to perform actions such as loop cuts or ring selections. This isn't to say that triangles and faces with more than four edges shouldn't be used, but quads are preferable.

Example use of these techniques:

Topology Flow: https://web.archive.org/web/20210423191525/https://topologyguides.com/loop-reduction

If you want to add more handy techniques, please add them.