Making Shabath Early

Can I do early shabbos?

Yes, making Shabath early is entirely acceptable.
Most people who do this, however, go about it incorrectly. Namely: one should daven Minha before P’lagh HaMinha, and then, after PHM, one can daven ‘Arvith, i.e. the 7 B’rakhoth of the Amidah or “Sh’mone ‘Esre”. One can of course also say/sing Qabalath Shabath, even though this is not a Hova.
One most definitely may not say Q’riyath Sh’ma with the B’rakhoth before sunset, and preferably one should not do so before Sseth HaKokhavim (the appearance of 3 stars). If one recites Sh’ma before the appearance of 3 stars, one must repeat it later at night.
This means that if one wishes to make Shabath early, one says Q’riyath Sh’ma later at night, and not before ‘Arvith. (Being “Somekh G’ula l’Tphila” is not a hova in this and similar cases – see Rav Hai Gaon quoted by Rosh, B’rakhoth 1:1).
This is the almost unanimous opinion of all the G’onim and Rishonim. It is also logical: how can one say “HaMa’ariv ‘Aravim” when the sun is shining in one’s eyes?
Rabbi David Bar-Hayim