It truly depends on whether you're doing AS or A2 Law. In AS, it's quite rare that you write more than two sides on a particular topic. But in A2, it's quite common as each exam question is 25 marks each.
For A2, I use the IRAC Method for each of my essays. I state the issue and the rule related to it. I, then, move onto the application of the rule to the scenario and conclude. For example;
I - Alice threw a vase at Beth, after she turned her back, the vase missed by inches and flew out an open window.
R - s39 CJA 1988: Assault
AR: To cause the apprehension of immediate unlawful force or violence
MR: Intention to cause the apprehension of immediate unlawful force or violence or recklessness as to whether such fear was caused.
Ireland - silent phone calls could amount to assault.
Constanza - letters could also amount to assault
Smith v Chief Superintendent of Woking Police Station - immediate did not mean instantaneous but imminent.
A - Alice threw vase at Beth when she turned around, with her back to Alice. Beth could not fear unlawful force or violence, if she couldn't see it,
C - Alice wouldn't be criminally liable for an offence of assault against Beth since she could not see the vase before it flew past her and out the window.
This would be one part of the overall essay.