My coworker taught me 5 ways to be better with money and I've already saved $400

I've never been a big spender, mainly because I've never had a ton of extra cash. But I'm not really a saver either: By the end of each month, I don't have much left over, thanks to the times I eat meals out or make purchases I don't necessarily need, like skincare products or clothing.

My coworker Kathleen Elkins is an extreme saver who has been living in NYC on only $60 a week for the show "Cash Diet." I've been editing the show, and watching footage of Kathleen not spending has changed the way I think about my own relationship with money.

Thanks to her tips, I've changed my behavior and already saved about $400.

Here's what I learned from Kathleen's cash diet:

1. Treat restaurants and bars as a luxury, not as a given

Unless I'm meeting someone for a business meeting or seeing a friend I haven't seen in ages, I don't eat out. I have been making more of an effort to prepare my lunches for the entire week so I don't spend money on food when I'm at work. I usually cook a big pot of legumes and rice and make some veggies.

I also make coffee and have breakfast at home every morning. If I'm out for a drink, I skip the $15 fancy cocktails and opt for a $7 beer or happy hour special. That usually cuts the cost down by half.

Lesson: Delete takeout apps from your phone and make time to go to the grocery store each week.

2. Quit memberships you don't use

I have been paying a gym membership for months without ever stepping foot inside the facilities. I used to go and have been telling myself that I'll go back, but it still hasn't happened.

I finally cancelled my membership and now have an extra $72 to save each month.

I also cancelled my $7.99/month Hulu membership because I rarely use it. It seems like a small expense but it adds up to $100 a year! I figured if I wouldn't light a $100 bill on fire, I shouldn't be paying $100 for a service I never use.

Lesson: Check in with the monthly expenses or subscriptions that automatically come out of your account. If you have to ask yourself, "Do I really use this that often?" the answer is probably, "No."

3. Shop your closet

In the past, I've felt comfortable buying something rather pricey if I thought it was high quality and looked unique. Editing "Cash Diet" made realize I already have a ton of clothing I barely wear.

I recently donated a giant suitcase of clothing to Goodwill and now I won't buy anything unless I absolutely need it and I am absolutely sure I'll wear it all of the time.

Lesson: Clean out your closet and get rid of the clothing you don't wear. Make informed purchases and spend your money on clothing you know you'll happily reach for in the morning.

4. Forego the $50 moisturizer

It used to be easy to justify spending $50 on a serum because I was taking care of my face. But, deep down, I knew better. The health of your skin is directly related to what you eat, how much water you drink, how often you exercise and how stressed you are.

The truth is, a $20 moisturizer can be as good and effective as a $50 one. I've now stopped investing in expensive skincare products. I keep things simpler, and it not only helps me save money but keeps me healthier in general.

Lesson: Expensive doesn't always mean better. If your $50 moisturizer is something you can't live without, pick a few other splurge items you can drop.

5. Figure out which saving tricks work best for you

Kathleen's biggest piece of advice is to use cash, but I have found that I tend to run out of cash pretty fast because it feels more accessible. Plastic works better for me since I feel more reluctant to use my debit or credit card.

Like Kathleen, though, I've been checking my expense log more and watching what I spend each day, and making notes of where I can improve.

Lesson: Pay attention to how you spend and save money, and go from there.

Organizing my spending habits also helped me realize my goals: I want to invest in my career, so saving and spending money to utilize there is a priority. Everything else feels secondary.

Now when I feel like ordering $20 takeout, I remind myself that's $20 I won't be able to put towards film and video production. Taking control of my money makes me feel more secure and less burdened by my own financial situation.