Hi Eric,
Well done on the purchase of a new 50mm f1.8 lens. These lenses are affordable but they are also exceptionally capable, particularly if you learn some of the tricks that go with the territory.
We live in an age where most of us think that we can take a photo in almost any conditions and the camera will work everything out for us. One of the challenges of working with this lens is that it does not have built in image stabilisation. This means that excessive camera movement will show up as blur in the final image.
Now, an old rule of thumb in photography is to take the equivalent focal length of the lens you are using (in this case it is 80mm as your camera, the EOS 600D has a 1.6x crop factor) and then treat that number as the slowest shutter speed that you should handhold the lens at. In this instance, a 80mm lens would mean that you should not hand-hold the lens at shutter speeds slower than 1/80th of a second.
Now in this image you made the photo at 1/16th of a second. That is five times (or 2.5 stops) slower than the recommended handheld speed.
“What can you do about this?” I hear you ask. One option would be to add more light. Another option is to increase the ISO.
This photo was made at 200 ISO but if you were to increase the ISO to 800 or 1600 you could increase the shutter speed to 1/60th or 1/120th of a second. With the faster shutter speed there becomes less risk of getting movement in the picture.
There is a penalty in using faster ISOs and that's noise. But given the choice between movement blur and noise it's usually better to go with the later. In my own work I often work at up to 6400 ISO.
I hope this is a help!
Cheers,
Anthony