Here are a few resources that Silver Mountain Instruction recommends
Dry Fire Practice:
Dry fire practice is an important training tool that will help improve your skills.
• You can do dry fire practice almost anywhere, Of course, avoid public areas.
• It is crucial that you TRIPLE check your firearm to ensure it’s unloaded and ‘dry’
• Place a target on the wall you want to use
• Rack your slide, cocking the trigger
• The gently ‘press’ your trigger until it breaks
• 50-100 times 3-4 times a week (smokeless range)