If you are just starting out with C2C crochet, the basic square is a good place to begin as it will teach you the basics of increasing and decreasing. There are written instructions for the pattern below, followed by a photo tutorial.
Abbreviations (US Terms):
CH = chain
DC = double crochet
SL ST = slip stitch
Written Instructions for C2C Square
Row 1: CH 6, DC in 4th ch from hook, DC in next 2 chs. Turn.
Row 2 (increase row): CH 6, DC in 4th ch from hook, DC in next 2 chs, SL ST into ch-3 space from beginning of row 1, CH 3, 3 DC in same ch-3 space. Turn.
Row 3 (increase row): CH 6, DC in 4th ch from hook, DC in next 2 chs, SL ST into next ch-3 space, CH 3, 3 DC in same ch-3 space, SL ST into next ch-3 space, CH 3, 3 DC in same ch-3 space. Turn.
Row 4 (decrease row): SL ST in first 3 DC, CH 3, 3 DC in first ch-3 space, SL ST in next ch-3 space, CH 3, 3 DC in next ch-3 space, SL ST in next ch-3 space. Turn.
Row 5 (decrease row): SL ST in first 3 DC, CH 3, 3 DC in first ch-3 space, SL ST in next ch-3 space.
To finish off, I like to turn my work and SL ST in the last 3 DC to the corner before fastening off my yarn. It’s not necessary, but I like the way it looks.
Photo Tutorial for C2C Square