How to Attain Peace? Sometimes we feel nervous, afraid, or anxious while doing something. So, How can we attain peace in afraid mood or anxious mood?
By acknowledging your anxious mood as a truth (dhamma). Don't push it away, don't try to change anything, don't blame or criticize yourself. It is a truth and therefore has the 3 characteristics of reality, namely anicca (it has beginning, middle and end), dukkha (it obviously doesn't satisfy you), anatta (you cannot control it; it arises due to certain conditions/habits/situations). Why should it be different?
As for how to actually deal with fear/anxiety, you could listen to this talk from Ajahn Jayasaro. He describes how fear/anxiety works. It has both a physical and a mental aspect. Fear builds up using a feedback loop. If there is a fearful thought, a reaction in the body follows, you become worried about your bodily reaction with your mind, which then causes more tension in the body ... You can break that cycle by staying with the body and watching the feelings/sensations there (more detailed in the video).
Being at peace means to be at peace with whatever arises, not getting things or mind states that are peaceful and dependent on external causes. Peace means you're never at war with yourself :)