Create three savings buckets
Separate a small emergency buffer, planned irregular expenses and a longer-term goal. You do not need to fund all three equally at the start.
Use a minimum and a bonus amount
Choose a small contribution you can usually manage, then add more in stronger months. This can be easier to maintain than an unrealistic fixed target.
Review, do not punish
If you miss a target because of a real expense, update the plan instead of abandoning it. The purpose is to make your money more visible.