Select an online program that best fits your needs. There are many ways to do this. Oxford, Cambridge and Ecce Romani offer free Latin courses. Also, the Virtual School of Languages offers different courses as well. Links to both are provided below. You can also take online courses from different universities that offer online courses.
Go through each lesson initially. While doing so, plan out a schedule for yourself. Observe each lesson and make an estimate on how much time each lesson will probably take you. Remember, this schedule is not permanent; instead, it merely serves as a guide and something to keep you "on your toes."
Read through each lesson. Perform each exercise as instructed in the lesson. If you are having trouble grasping something, go through it a second time. If you are still having trouble grasping something, perhaps try a different online course and see if it explains the topic in question in a manner in which you understand better.
Practice vocabulary. Write down vocabulary from each lesson in a notepad. Practice at least 1 hour each day. Drill yourself or perhaps have a friend drill you if you are so inclined. Make flash cards, word puzzles or anything that aides in your personal learning process.
Practice pronunciation. In the case of Latin, some students may just have the desire to be able to read the language, but if you wish to be able to speak it and understand it, record yourself speaking Latin. Bring your voice recorder with you at all times and practice whenever you can. This includes while running errands, walking to work or exercising.
Test yourself. Review each lesson and make sure you have a strong grasp on the material covered. Again, stay updated on vocabulary, especially your verbs.