Parents who prepare for PT meetings have made a good decision, and are more likely to get what they want out of the meeting. Preparing starts with having a definite goal for the meeting, and a plan to achieve the goal. There are some essentials. Attending a PT meeting while agitated, full of complaints and negative comments will rarely help a parent get those results. Being calm and focussed should be a parent's first goal. If you will need help to keep calm make lists - thoughts, ideas and questions in the weeks before the meeting.
Select the most important and take them to the meeting.
Don't be afraid to use them. Make notes during the meeting.
Teachers cannot begin to provide a full picture, a complete explanation, of a child's learning history in a ten minute interview. Parents who stay in touch with teacher's throughout the year have a better chance of understanding what the teacher's are 'really saying', and feel confident enough to make contact with the teacher regularly.
HINT: regular, conversational chats about practical things can start real relationships.
Finally, keeping it simple makes the most sense, so ... if plans, suggestions and ideas are discussed during a PT Interview, make sure you follow up.