Most of our skills are developed on the ground. When you begin working on apparatuses such as swing sets and hand rails, check your environment before you work. Stress test them for strength. If the bars are bending under your weight, then don't use them. Also, early morning dew and left over rain moisture will prevent good traction. I've also found playground mulch dust prevents good traction on poles. Some playground paints seem to discourage traction in certain temperatures. Be careful, be safe. There's nothing more frustrating than sitting out, waiting for your body to heal because you attempted something before testing your surfaces.

1. Sidewalk Cracks - I learned to jump from sidewalk crack to sidewalk crack on my first day. The goal is to learn the timing of the jump, specifically the arm swing and departure vector. The more momentum you can load into the jump, the higher/farther you can jump. This is essentially a "standing broad jump". However, when you land, you should land on the balls of your feet and absorb the energy of the jump with every muscle from foot to hips. The landing should be silent and there should be no pain from shock in your lower back.

2. Guardrail Support Posts - The supports posts for guardrails serve as an excellent intermediate environment before attempting handrails. The top surfaces are about 12" x 8", a good landing pad for the balls of your feet, and ~2' above the ground. Again, landings should be silent.
   
   WARNING: Be very careful on these as they are wood and tend to retain moisture long after the dew has evaporated from everything else.

3. Low Bars (pt 1) - Here is a way to reduce the surface area contact of your landing while keeping training height low. You can build a set of bars with some bar material and a 2x4. These tools will help you develop your confidence and let you feel when your landing was not as solid as you thought.
    
   Use an aggressive arm swing after your landing to counter your forward momentum. To do this, you'll have to bring your arms back in mid-flight.

4. Low Bars (pt 2) - After mastering the landing on the low bar, try jumping from bar to bar. Here you'll realize that the precision of the jump is much harder because of the takeoff.

5. Handrails - Always check these first. Years of use can make handrails loose in their concrete setting. If the bar is not solid, it will move under you when you land. I typically train on the sections of the handrail closest to the vertical supports. This is where the bar itself is strongest.