One of the most recent things I did with a first grade group and individual white boards was teaching them how to make contractions. You could introduce it and say the word "contraction" and have them tell their partner what the word is again. Then do the same with "apostrophe." You could have them tell their neighbor whatever they are going to write before they write it. You could use gestures such as taking something out, putting something in to replace it, and pushing together to make one word.
I've also used whiteboards with word families, such as "oat." Have them tell their partners what words have the "oat" sound in them and then bring them back together and have them share with you, and then have them write them on their boards. Instead of using different gestures for each different word, you can just have them use speaking gestures of excitement.