The term homesteading is usually associated with the Homesteading Act that allowed certain Americans to claim land before the law was done away with in the 1970s. However homesteading as an activity is alive and well and moving into the cities and suburbs of America and many other countries.
Homesteading goes by many other names; simple living, country living, getting back to basics and self-sufficient living. It is doing more for yourself and relying less on consumer goods and services. Urban homesteading is simply homesteading without the benefit of a large amount of land, such as in the city. Some of the ways people practice urban homesteading is by gardening & using Canning recipes & generating electricity, through the use of rainwater collection and greywater use. if you are interested in homesteading (urban or not) you should plan.
Are you interested in just growing fresh herbs and vegetables or do you want to go as far as creating your own clothes, furniture and home furnishings as well as grown your own food? The answers to these questions will have a lot to do with the amount of time and effort you want to, and can, dedicate to homesteading as well as the amount of space and resources available to you. The best idea might be to write a list of your ultimate goals and then start by working towards one at a time.
What you need to begin is going to depend largely on what you want to accomplish. To start container gardening you will need at least some large containers (they do not have to be flower pots, any container will do), some potting soil, seeds, and fertilizer if you decide to use a commercial product instead of going organic. Coffee grounds make a decent organic fertilizer if you do not want to but a commercial product.
If you are going to making your own clothes, obviously you will need a sewing machine, fabric, and other sewing supplies. Soap making has its own supplies as does candle making, canning, drying, etc.
you may be able to install solar panels. If you live in any apartment or residence that you do not own, you may have to settle for a small solar generator, or only a solar oven. You can usually hang your clothes outside to dry rather than using a dryer but some areas do not allow clotheslines to be hung so you have to check the local laws.
Simple living is not looked upon highly by most people in our consumer goods driven society. Odds are you will have friends and family members that will think what you are doing is pointless and over the top. Consider how you will deal with people criticizing the changes you are making, even going so far as to say that homemade goods are not safe or as good as those bought in a store. Above all, stick to your guns and do not let naysayers make you doubt that you are doing the right thing.