T-shirts must always be fitted. Otherwise, follow the rules for casual shirts.
You either want to wear a shirt that breaks up your torso and gives you shape or wear a plain shirt and let the rest of the outfit do the work.
You can go with something structured, a blouse that is gathered at the waist, or even a men’s button up with a belt at the waist. Any of these things will work for you. However, if there is no waist on your blouse you’ll need to add a belt or wear something that your blouse can be tucked into. Puff sleeves and ruffles on the bust are a good idea, too.
Wrap sweaters are great for boy shapes if they have a tie at the waist. Also, any plain sweater that you can add a belt to is great. I really like the mushroom type of sweater that is tight on the waist, but bellows out above the waist. Those are really cute for a boy shape.
You can wear a slouchy blazer if you add a skinny belt to it. There are some really cute blazers with elastic in the waist. Skinnier or shorter lapels on blazers with pockets on the hips will also do the trick. (A thicker or longer lapel will be overwhelming on your straight frame.)
Skirts and Mini Skirts:
I think it’s a good idea to break up your torso with a high-waisted skirt. High-waist skirts creat the look of longer legs, too. Skirts with wide waistbands are good for your shape. If you want to bring more attention to your hips, and create the illusion of curves, you can wear a low-rise skirt with a wide waistband – as long as it doesn’t give you a muffin top. Flared, bubble or cargo skirts will give you a little extra shape as well.
I DON’T RECOMMEND SKINNY JEANS FOR ANY BODY TYPE.
That being said… Low-rise skinny jeans are going to make your torso look twice as long and your legs look half as long. Avoid them. If you can find high-rise skinny jeans, those would be best. If you can only find mid-rise then make sure that you are breaking up your torso and cinching in your waist.
High-rise jeans will break up your torso, which can help to give more curves. Bell bottom jeans create the illusion of wider hips, but be careful because they can also shorten your legs. Your best bet is going to be a mid to high-rise bootcut jean.
I love a high-waist, darted trouser for boy shapes. An open dart on a high waist trouser will give you some shape. Make sure that whatever pants you wear are fitted to your rear. Fitted clothing can go a long way to defining curves that you don’t think you have. You can also wear low-rise trousers(be wary of muffin top) with a skinny belt. That will help to bring attention to your hips. Just be sure to balance that out on top. Width of the leg can vary depending on rise and the top you pair it with.
The best little black dress for you will be one that pulls in at the waist. If it’s cut in a way that creates some curves – whether it be a flowy skirt, a low neck line, etc. – that’s even better.
Look for a romper with a tie waist or an elastic waist. Your body type would look best in a 40’s style pleated romper with short sleeves and wide shorts.
If you are a boy shape (or rectangle or banana) then you have a very straight shape. Other than padding your bathing suits there are a few things you can do to give yourself some va-va-voom. My favorite two-piece for a boy shape would have a bandeua top with ruching in the center and a simple side-tie bikini bottom. You can add convertible straps to your top if you feel like you need them, but the shape of the bandeau top is going to break up your torso and draw attention to your bust – even if you don’t have much of one. Another way to add some shape is to look for a bikini with ruffles on the bust and booty. Looking for a one-piece? I got you covered, almost. Go for a one piece with cut-outs at the sides or lines that create an hourglass shape. Either one gives the illusion of a more shapely torso.