What is the secret to "tenses"
My biggest problem so far, is knowing when to use the correct tense.
Escribe, escribe, escribo, etc.
Is there a secret, out side of simple memorization?
All the verbs you learn in the first few lessons are in present tense. They are conjugated with the subject (just as they are in english: I write, but he writes). In Spanish, however, every person (yo, tú, él/ella, nosotros, etc) has a distinct conjugation. There isn't really a secret to remembering which correlates with which, though you get a pretty good feel for them the more you practice them. It might help to look at some verb charts and memorize the endings of regular verbs. Check out this page: http://www.studyspanish.com/lessons/regverb1.htm
Some verbs (e.g. ser) are irregular and must be separately memorized. Also remember that usted/él/ella are conjugated the same, and ustedes/ellos/ellas are also conjugated the same.
What I find helps is to always write out the personal pronouns ("yo escribo" instead of just "escribo") until you become familiar with them and feel confident dropping them.