Tips to make teenagers look more like teenager?

Parenthood came with some teen-ish looking clothes that I tend to use 99% of my teens. Also maybe it's just me personally, but I think a lot of the C&D clothes look fitting for teens. The animal prints give off a youthful vibe imo. Also certain clothes from Get Together look fitting for teens to me. Also youthful looking hairstyles like the twin braids from Outdoor Retreat look fitting for teen girls to me.

definitely acne helps. Hair and clothing makes a huge difference. I tend to have my teens be thinner as I think having them be heavier makes them appear older.

For females, unless I'm going for a goth type look...I have little to no makeup on them.

I've also noticed its better to age up all my adults who interact with my teens to adults vs young adults unless stacy's mom is around XD

I always use a lot of clothing for teens that look to fit their age range to look juvenile and casual. Graphic hoodies, graphic tops, sneakers, ripped/patched jeans, and colorful clothing. The knotted top with graphics on it from backyard stuff is perfect for teen girls.

I always make my teens a bit more round in the face. Add some details later when they age up depending. Though between idle animations specifically made for teens it's not too hard for me to identify them along with their voice. I still always give any teens a makeover.

Here's one of my teen boy sims. He's wearing a hoodie and a pair of jogger pants. Only gave him just a little bit of facial hair along with a stylish haircut. :p
https://i.imgur.com/D7Tb67m.png

And my Angela Pleasant I had made in game. Currently a teen. Simple dress for her, but I can tell she's a teen.
https://i.imgur.com/c4GO7Rs.png

Dress them as teenagers? as I play the sims 4 more It's easy to spot a Teenager, they have different facial structure than an adult, more pudgy faces, though with female it is pretty hard to differentiate.

I usually give my teen girls ponytails or the hairstyle Morgan Fyres wears and shy away from the shorter, choppy-layered hairs because (in my opinion) they make them look older. Also some of the braided hairs look a bit youthful to me. I dress them in jeans, hoodies, graphic tees, no low necklines or too much skin showing. For their formal wear I dress them in the shorter, ruffled party dress with the flats that came with City Living or anything else with little to no heel. I also add braces to their teeth. For males, I try to keep their hairstyles more playful than professional (I guess you could say), and add acne (sometimes). Also lots of graphic tees and the knock-off converse for both genders. Shorts and flip flops work too. You could also dress the girls somewhat Cassandra Goth to make it look like a school uniform as well. I've done that too.

Edit: The hairstyle on my sim in my profile pic seems more young adult to me than teen but I have used it on some teens. It all really depends on their personality.

Edit (again): As for make-up, I usually use neutrals to give the barely-there look, I guess you could say.

It’s funny I do the opposite of most simmers here. I give my teen females more makeup and clothing showing a bit more skin (short skirts, bare midriff etc). I guess it’s just me reflecting what I remember from being a teen in the 90’s. I had some wild outfits and makeup back then, but dress much more modest and hardly wear makeup as an adult. I give males oversized or super casual clothes with sneakers, and longer hairstyles. Some of my male teens wear ripped jeans and leather jackets with boots, just depends on their personality.

@Kita5399 I also allow my teens to show more skin. It seems to me that teens wear barely-there skirts, so that's what I generally choose. Sometimes I put calf-length leggings under the skirt and add trainers or ankle boots. I avoid the makeup altogether though.

I usually pick girly hairstyles for them, like pigtails, or coloured hair.

It's harder for the guys but, yes, like someone else said - ripped jeans, hoodies, trainers. No facial hair. Acne.

Like others suggested, braces and acne (though admittedly both are never used in my gameplay, but this has given me an idea). As for dressing, it depends on the personality for me. What’s their style, what are they in to, are they trying to grow up quick or are they satisfied with being a teen, what are their parents like and do they influence their teens clothing. I have some examples of some teens I’ve created and made over, I can add them here later.

@Kita5399 I agree with you -in my game young teen girls are so much more inexperienced with makeup so the tendancy is to slap it on heavily whereas as they get older they tone it down because they understand how to use very little to enhance their face - especially in these days of online makeup tutorials. So my teens start with thick overdone makeup and I tone it down until neutrals as adults and barefaced as elders. My young teens are more likely to wear the brighter colours or the more alternate clothing representing the scene they are into. They are either skin baring (as they have the figures - or wear oversized baggy clothes as they haven't come to terms with their changing shapes yet.)

I really like hearing the different way everyone differentiates their teens. It gives me different ideas to show different characters.

@TheMagnolia - yes i try to differentiate my teens by social status / family resources to buy clothes etc. too. Would love to see your makeovers.