I think と思います

This goes at the end to show that you believe what you say, but are not 100% sure. It is also used to show one's opinion. 　If there is a desu change it to da which is the more casual form and add to omoimasu

1. The speaker is not totally sure of the accuracy of his info...

熊のプーさん　は　くま だ　と　思います。
kuma no pu-san wa kuma da to omoimasu.
Winnie the Pooh is a bear, I think...

Next is an example of showing one's opinion.  It is true for the speaker, but may not be so for the listener.

なっとう　は　おいしい　と　思います。
nattou wa oishii to omoimasu.
I think Natto is delicious 

Basically you can say any sentence and if you want to soften it or show you are not sure, or show your opinion add to omoimasu