OK, shall do my best.
Chypre: True chypres originate from the Coty's groundbreaking perfume Chypre de Coty, which featured the distinct bergamot / oakmoss / patchouli / labdanum accord. These notes among others are typical of the natural scents native to the island of Cyprus (particularly the mossy woods).
So to recognise a traditional chypre look for those that feature a citrus / fruity top note (usually featuring bergamot) over a woody oakmoss / patchouli base. There are subdivisions within the family including green, leather, fruity, floral, animalic). Classic Chypres = Guerlain Mitsouko (fruity), Rochas Femme (fruity), Jean Patou Colony (fruity), Carven Ma Griffe (floral), Guerlain Chant D'Aromes (floral), Chanel No.19 (leather floral), Dior Miss Dior (leather), Paloma Picasso Mon Parfum (green), Gres Cabochard (leather, floral-animalic).
Fougere: This term is the french for 'fern-like' and is actually a fantasy note as ferns do not have a scent. The term is used to describe herbaceous mossy evoke the scent of a fern covered forest floor. This type of blend features notes such as sage, rosemary, lavender, basil, thyme with citrus (bergamot, lemon) high notes and a smooth woody base. It is easy to see how the lines are blurred but fougeres do not usually feature the incensy / ambery base of a traditional chypre. Classic Fougeres = Crown Perfumery Crown Fougere, Guerlain Jicky, Penhaligons English Fern, Paco Rabanne for Men.
Oriental: Personally, I see these perfumes as those that evoke the Orient through the use of traditional notes such as patchouli, amber, spice (vanilla, nutmeg, cinnamon), incense (frankincense (olibanum), myrrh) and exotic resins / balsams. They are deep, powerful, sensual and seductive. This covers an awful lot of ground these days, expecially with the huge sub-category of floral orientals (florientals). Classic Orientals = Dana Tabu, Must de Cartier, Dior Poison, YSL Opium, Estee Lauder Youth Dew, Serge Lutens Ambre Sultan, Serge Lutens Arabie, Caron Poivre.
I do hope this helps.