Usually unstressed "О" is pronounced as "A", and unstressed "E" - as "i". КорОва sounds like "karOva", молокО sounds like "malakO", гОрод sounds like "gOrad". рекА sounds like "rikA", прекрАсно sounds like "prikrAsna". Г - is g, but the endings "...ого", " ...его" are pronounced as "...ava" (or "...ova", depending on the stress), "...eva". Не вижу голубОго нЕба - sounds like "ni vizhu galubova neba".

By the way, pronunciation in Russian sometimes depends on dialect too. For example, "молоко" is pronounced "malako" by a Moscow citizen, but it sounds as written "moloko" when pronounced by a resident of the Urals. It's not literal. But there are some standarts in pronunciation. For example, it is standard to pronounce "чн" not as "chn", but "shn". "Конечно" sounds like "koneshno". It's standard pronunciation. But a citizen of St.Petersburg will pronounce as written "konechno". It's not standard, it's dialect.

— Why do certain words in Russian are not pronounce as how it is spelled? — Because it is Russian language. ☺ http://www.alphadictionary.com/rusgrammar/pronounc.html

By the way, correct spelling is ничего страшного, not нечего

Вы не ошибаетесь :) Though the Russian phonetics is much simpler than the English one, yet Russian words rarely sound exactly as they are written.