There is a variety of reflection for teachers to choose from. The most commonly used means are observation, journal or diary, and action research.
(1)Observation
 Observation is the most basic research technique we can employ in our classrooms. Teachers encounter many issues in classroom settings. Most of the rich data of classroom occurrences is gathered by the teacher himself or herself. However, these occurrences are seldom detected or immersed in some sort of reflection. Many teachers are more interested in completing the lesson plan they have organized (regardless its effectiveness) and never stop and reflect. Their daily lessons can be observed from different perspectives to gain insights on understanding their own teaching.  Observing our own teaching is a way of discovering the classroom from a perspective other than we actually engage in; it is a means of collective classroom-observation data and information about teaching (Wajnryb 1999). Reflective observation builds the groundwork for better relationships among colleagues based on mutual support and respect.
(2) Journal and diary
Another effective way of inquiring our own teaching and practice is by being committed in teachers’ journals. A teacher journal is often called a teacher’s diaries. A teacher journal is often a teacher’s systematic reflective teacher sack of what happened in a lesson according to either a prescribed format, or a more open-ended narrative. The task of keeping a teacher journal demands making entries regularly, preferably daily, if possible, and immediately after class. Very often its activity is inpidual. However, Richards and Lockhart (1994) have pointed out that colleagues can share a journal and get together to discuss it. These journal entries help teachers understand themselves，understand their classes, and understand both the teacher and the learner’s experiences as the lesson was developed.
(3) Action research
The idea of Action Research originated in the United States. In the 1950s, Stephen Corey (ibid) first applied theory to education. Action research is characterized by a continuing effort to closely interlink, relate and confront action and reflection, to reflect upon one’s conscious and unconscious doings in order to develop one’s actions and to act reflectively in order to develop one’s knowledge. ( Posch& Somekh, 1 993:6) From the definition chosen above, we note an important component of action research, that is, reflection, which is the most distinctive characteristic of the theory. Action research connects, combines and contrasts action with reflection making the practitioners reflect upon their behavior, consciously or unconsciously, with the purpose of improving their further action.
d) Process of reflection
Process of reflection consists of three stages, the recollection of the event, and review and response of the event (Richards, 1991).
Stage l: The event itself
The starting point is all actual teaching episodes, such as a lesson or other instructional event. While the focus of critical reflection is usually the teacher’s own teaching, self-reflection can also be stimulated by observation of another person’s teaching.
Stage 2：Recollection of the event
The next stage in reflective examination of an experience is an account of what happened, without explanation or evaluation. Several different procedures are available during the recollection phase, including written descriptions of an event, a video or audio recording of an event, or the use of checklists or coding systems to capture details of the event.
Stage 3: Review and response to the event
Following a focus on objective description of the event, the participant returns to the event and reviews it. The event is now processed at a deeper level, and questions are asked about the experience.
2.2 Teacher Professional Development
There is different understanding of teacher professional development from different terms, such as “staff development”, “in-service education”, “professional development”. This shows that teacher professional development is a more general term with more perse connotations. 反思性教学与英语教师专业发展(3):http://www.youerw.com/yingyu/lunwen_14320.html