How to compliment a thin figure

I’m 5′ 11” and only 129 lbs. I am 16 and have a size 28 waist. Needless to say, I’m small. I have a very lengthy body, but I also have a very athletic trim, so I’m not just thin thin. I also have “man curves.”
What I’m looking for are clothes that will compliment my thin figure. (Not JUST dress clothes, both please)
I’m always told how thin I look, whether in a suit (jacket off) or just casual clothes. I’m also told because I look so small I look awkward in jean. (Ouch)

I’m VERY confident in how I look, sometimes I have too much! I just always know I can look better. Help?

Non- standard proportion body type

I used to be a basketball player, which is the reason why I have broad shoulders. This would normally compliment a guys physique, but not so for me. I have kind of a small head. Which make makes my body look too big in proportion to my head. the broad shoulders just makes it worse. I was wondering what kind of advice I can have with regards to dressing in a suit, seeing that a suit usually makes a guys shoulder look broader,which in my case would not necessarily be a good thing. Also, are there any on more semi-casual clothing as well? Is there a certain type of shirt style or material that I should be looking out for?

What's the smallest suit size?

Hi, I am an average size man and have no problem finding my suit size. But I have a few petite-size friends who, even the 34 size jacket looks big on them. Is size 34 the smallest jacket size? If so, is custom tailoring their only option? (Besides trying to convince them to pump some iron, of course). Before hand, thank You!