Welcome to the forum. Usually soap operas are considered the best type of series to watch for everyday conversation, and it probably does not matter which one. But also try to read as much English as you can that has conversations, like modern novels. Reading a lot will have a positive effect on your English.
Friends is probably the most popular series used for learning English. Many of my language partners have used it. They say it's funny and not so hard to understand. Other often used shows are Lost, Seinfeld and Breaking Bad. What kind of series do you like? If you tell us, we can suggest some good ones for you. For example, do you like comedy? Crime drama? Romance? Fantasy? History?
I like crime drama, romance and comedy. I've been finished Friends series, but I think all of actors saying too fast to hard understand for me.
Many of the US networks (CBS, TNT, FOX, ABC, NBC etc.) have websites where you can stream a few episodes from current or past series, unless you are geo-blocked, in which case you could try a proxy server to connect. At first it will be hard to follow, but if you keep reading English and adding to your vocabulary especially by whatever means you prefer, your understanding will continue to improve, including for fast speech. And if 6 months later you go back to Friends, you should find it a lot easier to understand. You need lots of vocabulary and lots of exposure to English texts and speech to make progress. Good luck.
For romance, I think Sex and the City and Desperate Housewives are pretty popular. The Big Bang Theory and Arrested Development are famous comedy shows. 24 and CSI are good crime dramas.
If you install VLC media player, you will be able to slow down the playback of videos, and the dialogue will be easier to follow.
Doesn't work for streaming though. And I have yet to find capture software that works reliably in capturing both video and audio for streamed vids involving flashplayer. However if she can find vids on youtube, they can be downloaded in all cases as far as I have found with the proper Firefox add-on if necessary.
