These shirts are super easy. It wasn't until my third child was toddling around that I attempted to sew with knits. I was tired of seeing his long torso only partially covered by his shirts. T-shirts are either hit or miss--they can be too boxy, too short, the neck too tight....
To make a decent tee I took apart a favorite shirt that was stained, using it as a template I was pleasantly surprised at how easy it was to make. I have been making shirts this way for 11 years now and have come up with a few shortcuts.
Decent interlock knits are hard to find. For a child's shirt I scout out yard sales and thrift stores for extra large adult interlock polos or T- shirts. I used a Ralph Lauren polo for this red striped shirt. Sam drew the whale for me and I made it into an applique.
Most fabric stores have limited knit selection and the quality usually isn't too good. This time of year is when they have their best selection when the warm weather fabrics are in stock. Occasionally I will find a rainbow selection of rib knit (the neck lining) and will pick a few 1/8 yard colors to have on hand. If I can't find the appropriate coordinating colored rib knit I will buy a thrifted T shirt and cut the neck off and trim the rib knit to size.
Are you bored by this?
Henry will wear these shirts until about August when his two year old mock beer gut pokes out and/or they are covered with grape popsicle stains. Three of our kids have really long torsos and short legs, one has her Nana's really long chicken legs and the other has absolutely no butt. All the same it's fun to dress them when they are young. Around age 12 this changes and it is no longer fun to dress them. I was thinking of that show "What not to Wear" and it would be great to see a child's version. I have some contestants all lined up.