A few questions:

1) What are you teaching? Grammar? Vocab? Conversation? Reading? Writing?

2) Is this your first lesson plan in a 120 hour course? Did they give you guidance on things like structure? Like, intro concept, controlled practice, free practice, student interactions patterns, etc? With all due respect, I'd be massively side-eyeing a TEFL course that only required one lesson plan to be submitted right at the end - I also did a 120 hour, but was in class teaching, with lesson plans, from day 2. Teaching is inherently practical and the only way to get good is by doing. Online courses don't give you that experience, and you'll feel it hugely when you walk into a classroom for the first time (I'm assuming this is an online course, but my apologies if I'm wrong about that).

But anyway. I think I've been enough of dick - online TEFLs are my particular bugbear (sorry). With activities, try and make them as interactive as possible - group work, competition elements, make them move around. The specifics would depend on what you're teaching, and without knowing that, it's difficult to suggest anything in particular...