I want to make this plot much more nicer so its looks good and I tried all the things but any one can help me to make it more nicer and your suggestions are highly appreciated.
Thanks in advance.
The plot looks already quite nice to me. I would only write the legend label this way:
LegendLabel -> Style[T[x, y], FontFamily -> "Times", FontSize -> 12]
so that it has the same style as the PlotLabel.
The legend label does not work in contour plot so that's why i used the Plot legends.