When I am stuck for the type of thing I should say, or the way I should say it, I look at other people’s writing. Look for writing that is written for a similar audience, and not necessarily on the same topic. You can learn a lot from looking at writing on different topics too.
In this blog post Luiz Otávio has collated a whole lot of useful phrases that might help you get started with your sentences. He has really helpfully categorised them into themes.