rLately it’s a test period. Lately it’s a test period.

I must study more because I have to get greatmore point for schools on my test. I must study more because I have to get more points on my test.

It is possible to start a sentence with "because" but in this case you would want to connect the two clauses into one full sentence. If you wanted to start the sentence with "because" it might look something like this: "because I have to get more points on my test, I must study more." It's not incorrect to use "points" either but a more natural way of saying this would use "grade" or "score" instead (e.g., I must study more because I have to get a good grade on my test.)

bBecause I have to get great point for schoola good score on this upcoming test. Because I have to get a good score on this upcoming test.

This is because I have to get great points for the school test. This is because I have to get great points for the school test.

I will try it tommorrow. I will try it tomorrow.

You're using the future tense here so you need "will."

I will try it tommorrow. I will try it tomorrow.

I’ll try it tommorrow. I’ll try it tomorrow.

What are you trying to do tomorrow?

gGood bye. Goodbye.

Goodbye is typically written as one word or occasionally hyphenated as good-bye.