|See link below for simplest way:|
The above makes a large change. If you want just small changes then you can increase the taskbar size by increasing the Captions Buttons entry in Display Properties > Appearance > Advanced, which also increases the icon size. Unfortunately this also increases the title bar size.
Another way is to increase the dpi but this makes everything larger and if you take it too far some Windows might lose information outside the box. It is in Display Properties > Advanced.
Getting these the way you want them is something of a black art because the changes are inter-related. The last way is to decrease your screen resolution which again mages "everything" larger. Note that best clarity is when you match your screen resolution (which is probably how it is already set).
Please come back and let us know how you got on.