Making many drawing calls using just one API call!

Use Polyxxxx set of functions. Some of the functions that I know are listed below

1. PolyPolyline
2. PolyTextOut
3. PolylineTo
4. PolyDraw
5. PolyBezier
6. PolyBezierTo

From MSDN:

These functions exploit the fact that many drawing calls use identical attributes, and so multiple items can be drawn in a single call once the brushes, pens, colors, and fonts have been selected. For example, the console window uses PolyTextOut. This change significantly reduces scrolling time in a console window.