I saved $20,000 last year using travel credit cards. Here's how I get the most points without opening new ones.

• I travel a lot, and I like to use credit cards to earn points and save money.
• Credit cards earn rewards on everyday purchases, helping me save money without sacrificing travel.
• Opening new cards usually comes with bonus deals, but it's not the only way to get the best perks.

Now that I've figured out how to use points and miles to pay for airline tickets and hotels, I travel more than I ever did before.

Over the past year alone, I saved about $20,000 in travel costs by strategically earning and using points and miles.

I've found that the best way to quickly earn them is by opening new credit cards with generous sign-up bonuses. However, having a bunch of credit cards can make it difficult to manage your spending and feel overwhelming.

Plus, I'm not always able to spend enough to qualify for a new sign-up bonus if I don't have a big expense coming up.

So, I've started using other techniques to keep quickly racking up points and miles that'll help me continue traveling.

I use points multipliers strategically

Many travel credit cards give users one mile per dollar spent.

A few are more generous and give cardholders one and a half or two points or miles per dollar. This can add up through regular spending, but using multipliers helps me accrue miles more quickly.

For example, when I use my Chase Sapphire Preferred card at restaurants or hotels, I earn three points per dollar. My Chase Freedom card earns five points per dollar on rotating quarterly categories, which sometimes include groceries or gas.

By staying on top of which card earns the most miles for different purchases, I can earn more points faster than if I just pull out the first card in my wallet.

I try to book my vacations through travel portals

Many frequent travelers recommend booking hotels and flights with the provider rather than going through a third party.

This is generally good advice since it's usually easier to handle problems, like delayed flights, when dealing directly with the company providing the service.

However, I often ignore this advice and book hotels and flights through travel portals. After all, I earn five points per dollar when I book trips through the Chase travel portal with my Chase travel card.

To me, getting the extra points is worth the risk that I may need to make an extra phone call or two if something goes wrong.

Additionally, my American Express card gets me 35% of my points back when I spend them through the travel portal at the preferred airline that I selected when I opened my account.

Shopping portals help me get more points on purchases

When I first started seriously earning points, I didn't understand the power of using credit-card shopping portals.

However, I recently had a revelation when I went to send my mother flowers for her birthday. While using the Capital One app to pay my credit-card bill, I stopped by its shopping portal to see if I could find a florist.

I was astonished to find that I could earn 35 points per dollar just by ordering flowers through the portal. I've since earned more miles on everything from coffee to make-up by buying them through the Capital One portal.

I've found the Capital One shopping portal to be particularly generous with points, although other credit-card issuers, including Chase, also have shopping portals.

Rakuten is also my secret weapon for racking up points

Before getting into points and miles, I was a sporadic user of Rakuten, a different type of shopping portal that also offers rewards.

However, once I discovered that I could earn American Express Membership Rewards points instead of cash back, I started using Rakuten more often.

To earn American Express points, I only needed to link my American Express credit card to my Rakuten account.

Just like the Capital One shopping portal, Rakuten frequently runs great promotions. I recently earned 12 American Express Membership Rewards points per dollar by booking a tour using Rakuten.

Even better, I don't need to use my American Express card to make a purchase to earn those points, which allows me to earn points on two cards at once.

For example, when I used Rakuten to book a tour, I earned 12 points per dollar for making the purchase through Rakuten and another 3 points per dollar by using my Chase Sapphire Preferred card, which offers elevated points on travel purchases.