おかげで (or お陰（かげ）で in kanji) is an expression that is used to show thanks or appreciation in Japanese. It is usually translated simply as ‘thanks to (A)’, or ‘because of (A)’. おかげで is a combination of the polite prefix お, the 名詞（めいし） (noun) 陰（かげ） ‘shade’, and the 格助詞（かくじょし） で.
おかげで can be used after any word in its 連体形（れんたいけい） (attributive form).
We were able to finish work early, thanks to you helping us Takeru. Thank you so much for today.
Thanks to my room being so dirty, I don't know where anything is. (Sarcasm)
Thanks to my friend being famous, we can go to any fancy restaurant without a reservation.
Thanks to you, we can live a life free of inconvenience.
Literally, お陰（かげ）で means ‘in the shade of (A)’. This implies that (B) was only made possible due to (A) creating the ideal situation for it to occur.
おかげで may sometimes be used sarcastically, in the same way as ‘thanks to (A)’ in English. In these sentences, it is usually quite clear from the context/tone of voice that the actual meaning is negative.
Thanks to you saying something weird, I forgot what I wanted to say! (Sarcasm)
We have to work overtime again thanks to him. (Sarcasm)
おかげで is often used at the beginning of a sentence in the same way as ‘thankfully’ or ‘luckily’ in English. This just means that whatever comes after おかげで happened, despite negative outcomes also being possible.
Thankfully, I was able to pass my test.
Thanks to you, I was able to enjoy a nice holiday.