Ryan Rudolph wrote: focus more on renovations, buying out old properties that are not being used, and build up, rather then out.
Good news is that this is exactly what's happening around here. There are recent bans on development projects for office space for example, first one has to prove there's not any unused infrastructure around. Also a lot of urban developments have been suspended, but that's more because of the collapse of the buyer's and investment market. Renovating old property is not always the cheaper option though, depending on the state of the inner structure. Modern buildings are often not as long term solid and durable as older buildings.
2. Build Apartment building close to shopping and grocery stores, and Connect those areas through pedways.
You mean like inner cities
I notice demands for (family friendly) garden and private parking spaces making such apartment buildings less attractive for the market.
3. Community Garden areas that individuals pay to have plots and they can grow their own food even if they live in an apartment.
We have those here, and even worked on them occasionally, but land is scarce and waiting lists are in place. Also one often has to travel a bit to get there, which would conflict with idea #2, as why having grocery shops on walking distance while one has to travel way further for your vegetables? But good biking lanes and public transport options might be an option. Again, this is already a bit possible in many well managed cities. Price of land remains a problem though.
4. Focus on technologies that capture rain water as it falls rather then paying the city to provide water that is pumped in, treated with chemical, from fresh water lakes.
You mean something like gutters
and rain barrels attached? Not sure if rain water would provide enough in most places. People use it often to water their gardens with it. Rain water is not pristine either, government studies have found plenty of chemicals and hormone disrupters in my area.
Many sustainable solutions need a flexible, sustainable infrastructure to support it. So I'd stress large investment in public transport, underground common parking for cars, shuttle services to get to the parking lots, perhaps more plans for car sharing or rotation ("on demand"). Then one has to look at urban lot values and bring down the insane pricing which prevents community gardens and parks to develop. In the more free market based societies these things will never happen because the 'free market' is ruled by short term profit and sustainable solutions are not short term. Unless big investors will start to invest into long term, of course. Or the state.