Engineering stats simple question

Hi! I know how to construct a stem and leaf plot, but i'm having some issues with a data set. I've always learned to include the gaps because i thought that was one of the main reasons why we use the stem and leaf plot, but this data set is all over the place. Is it ok to leave out the gaps for a data set like this.?.. the current book we're using is quite awful in having examples and or explanations and my precious google has failed me. Any help is appreciated.

{30, 75, 79, 80, 236, 223, 232, 80, 232, 240, 105, 242, 126, 245, 138, 247, 149, 354, 179, 274, 179, 384, 191, 470}

I'll have to construct a dot-plot as well, and then a histogram. I guess I am just too used to "nice" data. So any insight on how to organize classes and the such would be helpful as well.