Form fitting shirt?

Form fitting shirt?

I have a few black unisex t-shirts I wear for work that are waaay too big for me, and they're smalls! I'm kinda petite and I'm lost in them because they're so big. I've already gotten my manager's okay for this; how would I go about just bringing them in a bit so they fit me better? I want them to be a little more form fitting, especially around my waist and fit me so I don't look like I'm wearing a pillow case. I don't own a sewing machine; would I need one? I can sew by hand. any tips?
My bedroom

My bedroom

Chelsea’s Room

Chelsea’s Room

Heligan gardens, Cornwall

Heligan gardens, Cornwall

Proper paint?

Proper paint?

Best Option for Money

Best Option for Money

Hello there domestic Divas.

Hello there domestic Divas.