In the advent of smartphones, I would suggest installing some budget apps where we can track our spending and record our budget for a certain month or year. I have one mine for years now. What I usually do is challenge myself to save more every single month and what I do is adjust some expenses on certain stuff that I have budgeted last month and when you do that, it will become a habit - a good and productive habit.
As for me, I do it in an excel file. I always use computer everyday so it's convenient for me.I keep track of my expenses like how much did I spend on food, groceries, transportation,clothing and other miscellaneous expenses and then set a budget for each kind of expense and see to it that my expenses for the month will not exceed the budget. Upon receiving my salary,I set aside a portion for savings then the rest will be for expenses. I see to it that I update my excel file everyday and I even write what items did I spent my money to and where did I spent it. Through this, I can monitor my expenses and spend only on the things that I needed. I started doing this last January 2015 until now.