Suggestions of further work you could do are generally recommended. Any problems you had - perhaps you had to make up a solution and couldn't be sure if you got all the solid dissolved, etc. Sometimes when you heat things you can't keep the temperature constant, you may have conducted different parts of the experiment on different days, solutions may not have been homogenous, crystals may not have been pure, etc. Anything that would have stopped it being a fair/accurate test.