Like most new adventures

my recent path of following the Markuz plan started with a bang and a lot of enthusiasm. January and February were low-expense months which made sticking to the budget fairly easy and fun. With a end of year bonus from work, tax returns, etc. I was able to make a lot of traction towards Baby Step 2 which was exciting.
March is starting out as the true test to what life on the BB plan will really look like. New clothes and shoes for the growing 10-year old, medical bills (smallish but unpredictable), car maintenance expenses, summer camp registration expenses for summer childcare, all of these expenses are coming in at the same time. I’ve been setting aside money each month for these things but was expecting some of it to come later in the year giving me time to save up a bit more. The budget is still good, but saying “no” has started to become a bit repetative. Last time I did the BB plan I got through Step 2 and then lost steam, over time I fell off track and ended up going back to my old ways. I’m selling my ‘fun’ summer car soon which will wipe out my debt snowball completely.
Once I get to Baby Step 3 I’m thinking of asking my employer if they would be able to do a payroll deduction and deposit money into a Money Market Account so that it’s not even in my working budget each month.
How do you all stay focused over the long haul especially getting through Step 3?