On no account look directly at the darkened Sun . A direct observation of the sun, without adequate protection, can entail irreversible damage to your sight, even during maximum obscuration of the Sun.
Only the special eclipse glasses (as defined in the European directive 89 / 686 / EEC), which have been certified (and carry the IT mark of conformity), can be used to observe the eclipse.
Another technique: turn your back to the Sun!
In the absence of the special eclipse glasses, the safest way to observe is the indirect method, i.e. by projection.
Just make small a hole in a stiff sheet of paper or cardboard, and place it in front of the Sun, and a screen of stiff white paper behind the cardboard. In this way, an image of the Sun will so be projected on the screen. The fartherr the screen is from the hole, the larger will be the image (for a separation of about a meter, the the size of the solar image will be about 1cm). A simple shoe box can can do the trick. With its darkened interior, the heightened contrast will ensure that the solar image will be well visible A small square opening in the box is of course needed to actually see inside.