A lot of sustainability can be gained in design. Things like passive solar design, collecting rainwater and reusing grey water, having a vege garden and compost.
Strawbale is a great insulating material so it will cut down your power costs in summer and winter. If you use it as infill rather than load bearing you can have a much larger design.
You can also look towards non-Western and traditional design for sustainability. The Japanese system of sliding paper doors is fantastic. You can reduce space in winter and create cells of warmth rather than heating a whole house and in summer open the spaces to so that breezes flow through. Huge glass windows are a massive drain on resources because they create such an efficient energy exchange. Shutters don't take much to install and if you pull them closed over night in winter and when the sun is shining on your windows in summer they make a huge difference in heat loss/gain. Mexican and North-African designs often translate really well to our climate.

One thing that I do is when I see an idea or feature that I like I take a photo of it on my phone so I remember it. I have a file on my computer for photos and links of stuff I like.