Organizing Your Class
Syllabus
Your lecturer should have a syllabus, and ideally you should have a copy of it before the course begins. It is not unusual to get a copy at the same time as the students. You should also have a syllabus for your discussion section. Do not write or present your syllabus before the lecturer. Wait until you know exactly how they want to do things, since their policies trump yours.
A syllabus is more than a list of dates and topics. It should include your contact information (name, office number, office phone, e-mail), your office hours, policies, grading scheme for your discussion section, etc. The lecturer decides policies first. Your policies cannot contradict the lecturer's policies. If you have a problem with your lecturer's policies, discuss it with them outside of class or talk about it with your TA coordinator. You talk about your syllabus in class and give your students a hard copy. This is everything you can realistically do to make this information available to the students. It also prevents them from saying, "But I didn't know..."
Course Website
A course web page, for one, is a great place to keep a copy of your syllabus. In general, it can be an invaluable resource. It is a readily available place for students to find out about policies, assignments, test dates, etc. If you have no idea how to make a web site, start here or ask someone who does. Even though you aren't required to make a course page, it is very easy, it is good professional development, and you will be doing your students a huge favor.
Office Hours
You must have 3 or more set office hours per week. Decide what these hours are at the beginning of the semester and stick to them. It is okay to choose these hours to fit your schedule, but try not to be unreasonable. It is impossible to find a set of hours that every one of your students can use, so "by appointment" is also a fair option for one of your hours. There may be times in which none of your students show, so it's OK to use that time to do your own things, as long as you can easily be found and your students are your first priority for that hour.
Office hours are a chance for students to get extra help, to make up quizzes (if you allow this) or to discuss sensitive matters. You do not have to have perpetual office hours. It's okay to tell a student they have to leave once your office hours end. Similarly, e-mail is a great way for students to contact you, but you do not have to answer their mail on a 24-7 basis. If you decide to use e-mail as a way of hearing from your students, announce a response policy - e.g. 'E-mails received by 9:00PM weekdays will get a response by 9:00PM the next day.