Quick start using python and sklearn kmeans?
This has been answered in other places e.g. here.


You could run Principal Component Analysis (or other dimensionality reduction techniques) and plot the cluster for the first two principal components. 
You could plot the results for two variables at a time.
You could encode third or fourth variables using standard visualization techniques like color coding, symbols or facetting. 
There are ways to visualize the quality of the fit e.g. silhouette analysis or elbow test for determining the number of cluster etc.
Have a quick look at this link