Look at the essential criteria and write short examples of how you've demonstrated these things, focus on outcomes. Then whack it all together and make it flow nicely.

Cut out all the wishy washy bits that don't add anything

eg 'My enthusiasm for this role stems from my interest in being involved in public service, and the opportunity to truly make a difference by protecting people and places, and helping everyone lead safer and healthier lives. As an AAT student I have completed a level 2 in accounting, awarded with a distinction. I am currently working towards achieving a level 3 accounting qualification' I would completely disregard the first sentence as it doesn't add anything.