Basic thumbnails sketches

Today I was drawing some thumbnails using basic one-, two- and three-point perspective to see how it's applied. Learned a ton of stuff and already doing more of these, but this time adding some value.

Also a new oil painting is on the way. Just finished up sketch phase, this time really payning attention to proportions and construction. I hope I won't get into major mistakes during applying paint. Guess what? It will be portrait of my girlfirend. I know, I'm kind of surprising...