General Application Timeline... 
Junior Year
Spring/Summer- Start researching graduate programs and potential faculty advisors.
- Send out requests for information from schools.
- Determine application procedures, exam requirements, and application deadlines.
- Study for and possibly take required entrance exams.
- Think about additional classes you may need for senior year.
Senior Year
September/October- Request letters of recommendation from faculty.
- Take required entrance exams if you haven't done so already.
- Contact prospective faculty advisors.
- Start preparing your application materials.
- Write drafts of your personal statement.
- Inquire about assistantships/funding and research other financial aid possibilities.
- Order transcripts.
- Mail applications (possibly earlier, depending on the program).
- Apply for assistantships, fellowships, and grants.
- Arrange school visits and schedule an interview (if applicable).
- Make a decision.