Begin your risk assessment where everyone responsible is present; include all project stakeholders if necessary. Have in depth discussion regarding the project and then use a white board in a four-square format to help identify possible risks. As the team leader, once the meeting is over, it falls to you to assess each possible risk to determine if they are indeed in the right category: Avoidance, Reduction, Transfer or Retention.
Once you're comfortable with possible risks and their assigned levels, document in your risk management plan steps on how each risk will be handled. If the risk is avoidable from the get go, make sure it is specifically explained. If the risk falls in the reduction level of risk, in your risk management plan, document what team or team member will mitigate the risk. If the risk can be transferred, make sure you define the risk and choose appropriate resources to deal with the risk. If the risk is an acceptable risk, document your plans on how you will retain the risk and pay for the risk's outcome.
Assessing and transferring the level of risk in project management will ensure successful project outcomes. Prudent project managers understand risk much like author David Viscott, "If your life is ever going to get better, you'll have to take risks. There is simply no way you can grow without taking risks."
To put this into perspective when dealing with and assessing risk levels, keep in mind that it is almost humanly impossible to determine each and every risk. With experience comes less risk in future projects. If you avoid identifying, assessing, and transferring risks, your project's scope and outcome will be far different that what you expect.