Recognize that math is all around you. Sure there were some subjects in school that you never thought that you would use or need. There were even some facets of algebra or even geometry that weren't applicable to your day to day life. Notice all of the times that you use math during a week. Do you figure out the next time you will need to buy gas? Do you know how much interest you have to pay on a loan or mortgage?
Keep running totals. If you are at the grocery store, add up how much money you've spent as you put each item in the cart. The simple addition will keep your mind thinking about numbers. If you have a long line to wait in then add in your state's sale tax & see how close you can get to the actual total.
If you cook or want to win at trivia, learn how to convert different units of measurement. Become familiar with basic things like how many teaspoons are in a tablespoon. That way you'll be prepared if you're ever on a game show & the host asks "Which is bigger a liter or a gallon?"
Ditch the calculator. If you are balancing your checkbook try doing it without your calculator. This way you'll become more dependent on your brain to do math. Just make sure to check your calculations the first few times that you try it.
Give real numbers instead of estimating. Every time you say "Well it will be about..." you are estimating instead of coming up with a real number. Trying to come up with a concrete number will take a few more seconds but it will also help your math skills.
Create story problems. Most people hate those math problems that went something like "If a train leaves New York at 9:00 & another train leaves San Fransisco at 10:00 what time will they meet?" Story problems get your mind thinking about math in a new way. If a problem seems too difficult, change the names to people you know or try & make things more relatable.