The length of meditation will impact on how successful it will be.

• One study reported 5 hours' worth of meditation over a two-week period was enough for smokers to reduce their intake.
• Another study noted that regular 30 minutes meditation sessions can increase the density of brain matter in areas associated with memory, stress and empathy.

10 minutes a day can be enough when it is part of a daily routine. Longer periods might be required if it is done less frequently.

It is not possible to always be successful with your meditation sessions. 

Acceptance of the outcome of a meditation session is a factor when considering if it has been successful or not.

Try multiple settings to find which place suits your personal meditation style. 

It could be a dedicated spot or a useful place that also serves other purposes.

• A valuable tool to understand your own style is to keep a journal. It can help you to work out the similarities and qualitative considerations for multiple types of meditations.
• Neurofeedback devices can provide actual quantitative measurements of brain activity during meditation.
• Feedback sessions with your mentor can also be beneficial.

Developing a meditation style should not be a self-optimization goal. 

You may find more success if you develop your own style along the way to a wider set of meditative purposes.