My relationship is on thin ice how can I better our communication?

Maybe take some time to think about it and consider what's been going on, and whether it can even be fixed? You have to take into consideration your partner's way of handling things and personality.

Sometimes we can calmly talk things through and compromise/come to agreements. Other times we can't because there is too much BS.

All you can do is try.

If the people in a relationship cannot find a way to tell each other what they need, what they want, and what they appreciate in each other, the relationship is skating on thin ice. 

say short sweet things from time to time make her feel like she or he still matters

Be honest and talk to each other