Add all *.cpp and *.h files from QWT project directory to your project (best if you copy them under your program directory, so shorter path is enough).

Add these to your <your application>.PRO file:

QT += svg
INCLUDEPATH += <path to qwt>/qwt

Take one of the examples for playing with and include the source/header files of it also in your project.

E.g.:

CpuPlot *cpuPlot = new CpuPlot;
QVBoxLayout *layout = new QVBoxLayout;
layout->addWidget(cpuPlot);

Voila, that's all! Don't rob your time with compiling QWT, including DLLs or other complex stuffs.