Come up with a story for your kung fu movie. Even the most action-packed film needs a logical progression of events outlying why the combatants are fighting and what they hope to achieve by doing so. Structure the drama with a clear beginning, middle and end, charting the characters' progression and development in the process. Be sure to include plenty of scenes full of kung fu action, but give those scenes a logical connection to the overall plot.
Find some actors to star in your kung fu film. They should have a strong knowledge of kung fu fighting techniques and be able to pull off some moves that look very impressive onscreen. Expertise has another important benefit: safety. Kung fu experts who know what they're doing run a much smaller risk of hurting themselves while shooting a scene.
Hunt down some good locations to use for shooting. Your home or back yard works well: You can shoot there without a permit and tailor the surroundings to match what you want. Public parks are a good possibility as well, though you'll need to watch for other park-goers (who have as much right to be there as you). In addition, if you have access to a gym or fighting school, see if you can use their facilities for shooting.
Work out some choreography for each of your fight scenes, including the moves of each combatant and the position of the camera. Planning and rehearsal are key for fights. You want to make it look authentic without accidentally hurting anyone. If you have some awesome moves you want to plan, figure them out with the performers and work on them so you can shoot them safely. Keep an eye on your surroundings and note any dangerous or potentially dangerous spots. Don't go off script when shooting your fights: Know everyone's moves, and make sure your cast does, too.
Rehearse the talking parts of the movie as well--the moments between the fights that string them together and make them a coherent movie. Though not as dangerous as the fight scenes, it pays to get familiar with the dialogue, rehearse the various exchanges and locate good camera angles with which to shoot them. That lets you spot any problems with lighting, blocking or location before you shoot. In addition, performers selected for their kung fu prowess may be less comfortable with straight acting, and rehearsal time gives them a chance to feel at home with their dialogue.
Shoot your scenes one by one, using the choreography and camera placement you mapped out. Be prepared for delays and reshoots if your footage doesn't contain the elements you want.
Edit your film together using editing software on a personal computer. Add titles and credits as appropriate. When it's done, invite your cast and crew over for a screening or email copies of your kung fu film to them.