Hi Jrt,
I am also new here. But here's my advise.
Your depth of field is great. (Background blurry, subject in focus), This is called Bokeh.
But the subjects in photo 1 and 4 could use more focus. I believe this has to do with the aperture settings you used.
Try taking several photo's of the same subject with a different aperture. You could also try to set your camera on the Av mode. This way you don't have to adjust the shutter speed.
I like photo 3, great job.