Let's say you get your electric bill on the 23rd of each month and it is not due until the 3rd of the following month. By matching revenues and expense to the period in which they occurred, you will be able to determine if your monthly expenses exceed your monthly income. Make your best guess for some those items that are not reoccurring. It may take you a couple of months to get good at estimating the more difficult expense categories. If you find you have a large amount of money in any one category, consider breaking it down into more detail.
Utilities is a good example.
You need to keep track of your actual expenses incurred during the month and group them into these categories. If you don't have a memory like a steel trap, carry a small pocket size note book with you and write them down as they are incurred. Or if you find that to be a big pain, you can take the easy, but much less accurate, way out and each time you withdraw cash, guess which categories these cash expenses will fit into and record them. You can always adjust them later. You are welcome to download my budgeting software for free from the download page to help you keep track of all of this data each month.