Need help creating a basic tee shirt. critiques appreci Sewing Machines Parts and Sales in Los Angeles

I want to make most of my own clothes, i have decent vision for what i want to create. I spent ages trying to find a pattern for just a basic tee-shirt. You know, the shape that band tee shirts come in etc etc, but i wanted it to be well fitting. I could find literally nothing to help me. There was a few guides on creating a your own pattern for a tee shirt, but they were large and overwhelming and often not in the style i wanted.

CVommercial sewing pattern usually have a kind of style to them that doesn’t appeal to me, like a kind of dated feminine touch. I eventually settled on modifying the Butterick /fast & easy/ B6100 pattern as it had a kind of tee-shirt like pattern included.

So now i’ve finished what i thought would work and i’d love a bit of help since i seem to have messed up along the way. I’m pretty new to sewing, i’ve made 4 garments but i’ve still not gotten the hang of fitting things properly. I’ve mostly just followed the patterns fairly closely with a few minor modifications.

Here’s the album! http://imgur.com/a/69rsi

Problems I would like help with:
-Neckline – it’s far too wide. I decided to stray from the pattern by using some black ribbing for the collar but it seems to have had the effect of making the neckline too baggy. I would like to know if there is a way to fix this on this particular garment – if not, how i could avoid that in the future.

-Bunches up around the tits. It’s fine if i tug it down and smooth it out, but the minute i put my arms above my head, the bust darts end up above my bustline and give me that extremely attractive look like i’m carrying my boobs in a sack.

-A bit tight around the hem. I used my own measurements and plugged them into the pattern as im fairly thin but have larger breasts, but it seems to have all gone a bit wrong.

And if you can see anything else wrong technically, i’d like to hear about it!!

Specs:

Materials – Wax block printed cotton, tubular knitted acrylic for the neckline, jersey cotton for the sleeve cuffs.

Cotton thread, a singer straight stitch machine, a singer serger.

My personal taste – Structured garments that fit well, i’m bigender so i don’t like my things to look too feminine or too masculine, but i do like to utilise the shape of my body.

Thanks in advanced!!! ?