These days airlines are charging for checked bags unless you have one of their special credit cards. My son travels often and has a Jet Blue Card so he doesn't pay for a checked bag. I don't fly that much so it's not really worth it for me. If you can fit everything you need into a carry on bag it will save you money.
This past summer I few to Los Angeles for the first time. A whole week of things that I would need made it into a carry on bag. The first tip comes from me. Buy yourself a nice carry on bag that is guaranteed to fit in the over head compartment. The bag my kids bought for me as a birthday present was the perfect size with a good amount of room.
Now here are those tips from flight attendants:
1. Plan around your shoes first. Limit how many shoes you bring and take flats or flip flops when possible.
2. Use packing cubes. Light weight pouches that keep everything neat
3. Pack good clothes in plastic. Wrapping nicer clothes in plastic keeps them smelling fresh.
4. Don't forget your swimsuit
5. Stay basic- People always think they need more than they do. Stick to basic colors and clothes that can be mixed and matched so no one notices you are wearing the same things.
6. If it doesn't fit in the bag. Wear it. Planes are usually a little chilly. Wearing an extra piece of clothing shouldn't be too uncomfortable.
7. Buy the small size toiletries and medicines you need and pack them in a pouch. I actually brought a prepacked pouch of everything I could possibly need for a few bucks at Walmart.
Here a picture of me before I left the radio station last summer.