Planetamy, I have a tendency towards inverted triangle. My bra band measurement is the same as my hips, but my shoulders - by measurement - are a tad broader. By visual, they look broader than what the tape measurement reads. I guess that's because my shoulders are straight across and strong.
I have very little problem finding jackets and tops that fit perfectly in the shoulder, so I tend to think I'm more "average" and this tendency is slight. I tend to think that it's my narrow hips that give me the appearance of inverted triangle, rather than broad shoulders dwarfing my average hips. Does that make sense?
One thing about my shoulders however is that when I gain weight, I gain weight in my back. So they may not be all that broad, but yes, gain a few pounds and I start to have some fit issues in my shoulders - the jacket at the back of the neck won't lay flat - but I think it's more because of excess back fat. Also I gain weight in my upper arms, which doesn't help matters.
My shoulders do go straight across - no sloping at all. I may gain weight easily and first in my upper body but if I weight train I also happen to build muscle in my upper body very quickly. I haven't weight trained in years but when I did I would quickly get lots of definition in the shoulders, arms, back and chest.
My DD14 is very similar shape to me and she's a swimmer. The effects of years of competitive swimming have given her some serious shoulders! She is very much an inverted triangle, particularly during swim season. She has lots of difficulty finding tops and jackets to fit her broad shoulders.
Whereas my DD16 is a pretty pear and she has very very delicate upper body, with slightly sloping shoulders. She has lots and lots of trouble finding tops, but I don't think it's because of the slope of her shoulders - they are just teeny tiny and narrow! (Also she has a long torso - if it fits her shoulders, it'll be way too short on her).
Ana gave you some good suggestions already, although I will say I have never ever liked dolman or kimono sleeves on me, and I frequently break the rules and wear puff sleeves anyway (it's not frequent but yes I have one or two items with puffy sleeves). And, I adore boat necklines for some strange reason! I guess because as I age I want more coverage for my chest, and crew necks look awful on me but something about a boat neckline is flattering.
One trick I've learned is to keep the shoulder line strong - don't bother softening it - and instead build up the hips so they look wider and more in balance. So if I do wear puff sleeves I might pair them with an A-line skirt instead of a pencil skirt. If I do wear a boat neckline I'll pair with trouser cut jeans that are wider than bootcuts. Etc.
Otherwise, I would say, skip the spaghetti straps and strapless. In fact, if you hate how you look in these two items, the chances are good you have broad shoulders. Halter tops look really good on inverted triangles. (I prefer halter type bathing suits for this reason). Sleeveless is great - provided it's not a spaghetti strap. For jackets, no shoulder pads. A vest is awesome for those with stronger shoulder lines too.
