I just started trying to to live by a budget and it has been a struggle, because there is no such thing as a typical month.
It's not like we will decide not to purchase any more food for the month, because we have already used up the food budget.
I set up my budget in Mint, with the automatic rollover, so that it averages out over time. It'll start March's budget with February's leftover amount. It has definitely helped me limit my spending on entertainment, checking mint right now, I can see that I went over my entertainment budget by $33 last month, so it reduces this months budget by that amount. There are some things that I wanted to purchase, that I will probably delay another month.
The biggest improvement in our food budget has been from meal planning. If we list out recipes for the week and do our grocery shopping on sunday, then we eliminate the temptation of eating out, because the menu plan is written on the whiteboard in the kitchen. Also, when cleaning up dinner, I package some for the next days lunch, which eliminates another temptation to order out. Focusing on my habits and what triggers them can reduce spending without feeling deprived.
Narrow down your categories better than just 'shopping' and it'll be easier to adjust your behavior. One of my addictions is tools, I will never have enough tools, but when I get a new temptation, I spend some time using some of the old tools and focus on appreciating the things that I already have. If the problem for you is clothes, then go shopping in your own closet and rediscover some of the older things that you haven't worn in a while. Focus on your behavior and figure out what is triggering that behavior.