B&B:

Coherence and cohesion:


http://grammar.about.com/od/tests/a/Exercise-In-Identifying-Transitional-Expressions.htm 
Pick up the transitional words and phrases used to provide cohesion 


http://grammar.about.com/od/developingparagraphs/a/cohrevisepars1.htm 
Use transitional words to link sentences into unified paragraphs.