School days are coming quickly, and that means it’s time to hit the shopping trail for cool new clothes.

Looking cute and trendy those first few weeks of school is key.

The annual tax-free shopping weekend begins Thursday in Georgia and Friday in South Carolina, so before you head to the stores to spend your part of an estimated $18.4 billion, find out what’s hot and what’s not this year.

For teen girls, those summer dresses and layered tank tops can head back to school and still be trendy. If you want to wear your shorter skirts, put on a pair of leggings underneath and — voila! Instantly within dress code.

Dresses aren’t always plain; they sport ruffles, prints and hoods. They’re baby-doll style, T-shirt style and kimono style.

Nice and cool for these terribly hot last days of summer.

For chilly classrooms, put a printed T-shirt under the dress or maybe a cropped jacket over it.

The best fashion advice for students this season: Layer everything. Layers are trendy — for girls and for guys.

Boys can wear a short-sleeve shirt on top of a long-sleeve shirt, or a T-shirt underneath a polo. When the weather cools, that same polo (or any other collared shirt) can be topped by a sweater.

Zip-off pants are another new trend, especially cool for the first hot days of school. The legs zip off at the knee, making a fabulous pair of pants into shorts.

Of course, denim is big again this year in back-to-school fashion, just as it is every year.

For girls there isn’t too much change, mostly darker washes.

“The big change in denim is that we’re seeing less of the skinny jeans and more of the wider leg,” said T.J. Maxx fashion spokeswoman Sonya Cosentini.

For guys, darker and cleaner washes are also hot.

So get out there and shop until you drop — or at least until your parents drop.

For gals

• Keep cool (and look trendy) in a dress.
• Plaids and patterns are in.
• Ballet flats are the perfect accessory.
• Layer a T-shirt or tank top underneath a dress.
• A belt around the middle adds a bit of flair.
• Don’t wear a belt over your shirt if you have a larger stomach.
• Boot-leg, flair-leg and wider jeans are back in style.
• Boots will take center stage as the weather cools.
• Accessorize any outfit with a great set of jewelry.

For guys

• Patterned T-shirts are always a good buy.
• You can’t go wrong with a new pair of sneakers.
• Layer your shirts.
• Throw on a jacket to keep warm and casual.
• Jeans are a great investment and can be worn year-round.

Accessories for girls

• Adding a headband will automatically update any outfit. Headbands with tails are super hot.
• Wedges are making a comeback.
• Wedges give more stability than a stiletto.
• Girls are using big purses instead of backpacks.

A few monetary predictions

• Families with school-age children spend an average of $563 on back-to-school merchandise.
• Out of that, an average of $231.80 will be on clothes.
• Families will spend about $94 on school supplies.
• Total back-to-school shopping in the United States is expected to reach $18.4 billion.
• U.S. shoppers will spend $7.6 billion on clothes.
• Teens will chip in an average of $31 of their own money.
• Families will spend 13 percent more on electronics than last year.
• Families will spend 10 percent more than last year on shoes — about $108 each.
• Pre-teens will spend $15 of their own money.

Source: National Retail Federation