Rookie...I just noticed your post. Don't be discouraged that no one else has responded yet...there are a lot of topics on the forum, and sometimes some go unanswered for a while, while others get a flood of responses. For instance, I don't have your specific info., but I wanted to let you know we're here!
I will tell you some of the mistakes many people (and I) make with houseplants. 1)overwatering...most houseplants like their roots to get slightly dry before watering.
2)overfertilizing...this can burn a plant, stress a plant so that it is prone to disease, or grows so fast that it gets leggy or falls over.
3)improper lighting...most houseplants like bright, indirect light. Many plants get too little light, but direct sunlight on the leaves of many plants will scorch them, even in winter. Supplemental artificial light should help the benjamina, if natural light isn't adequate.
4)repotting too soon, or allowing a plant to get rootbound. Repotting can make a plant go dormant for a while, but it becomes necessary, and only necesary, when the inner wall of the pot is a solid mass of roots, or roots are aggressively growing from the bottom of the container.
Good luck, and check back with us!