some important...words

firstly / first of all / to begin with / to start with
secondly
thirdly

finally

In my opinion / view

To my mind...
I am convinced that... (jestem przekonany ze)

It seems to me...

I am inclined to belive that (sklaniam sie wierzyc ze) / I think that...

Moreover (ponadto)
Therefore (dlatego)
Furthermore (ponadto)