Write the question first
Is the uncertainty about the outcome, process, price or fit? A service business might compare a process demonstration with an explanation of the problem it solves. Those test different concepts.
Build distinct ideas
Give each concept a clear message and purpose. Use approved assets, make the offer recognisable and check that key text works on a phone. Keep the intended action consistent unless testing that action is part of the question.
Match the comparison to the budget
The number of variants should reflect the available spend and activity. Too many similar assets can leave each with too little evidence to judge. Record how much delivery each one receives.
Choose the useful outcome
For awareness or engagement, use the measures agreed for that goal. For leads, review useful conversations as well as submissions. For sales, review purchases and cost. A comparison inside a normal campaign is a practical learning exercise; use a controlled experiment when that is the question you need to answer.
Read the whole journey
Check the destination before rejecting an idea that attracts useful clicks. Allow time for outcomes to develop and keep the test open when there is too little activity to make a decision.
Keep the learning
Record the question, concepts, period, spend and useful outcomes. Decide what to develop, revise, stop or test next.
Make a test card
Illustrative question: will showing how a detailing package works produce more suitable enquiries than showing only the finished vehicle? Record the two concepts, the same offer and destination, approved assets, spend, dates and the definition of a suitable enquiry. Compare delivery and follow-up outcomes. If one receives very little delivery, record that limit instead of declaring a winner from the raw lead count.