I am going to Tokyo and staying in Shinjuku. Where is a nice place to eat?

It's the season for unagi don ! Look around !

Quick and easy and lots of range: depachika. There are a couple of department stores in Shinjuku Station, and recently I was in Odakyu's. I got a lot of yummy things for about 1000 yen, and was able to feast in my hotel room.

Otherwise, it's really just a matter of walking around. Almost all of the restaurants have photo-menus outside their doors, and you can smell the great places. Pay attention to the restaurant floors of hotels and department stores, too.

That would depend on your budget/price range and what type of cuisine; there are more French and Italian restaurants in Tokyo than most cities in the world except of course for those in France and Italy. And Tokyo is one of those places in the world where you can spend a fortune on anything if you want and that includes dinner for 2 at $1200.

So what is the price range and what kinds of food do you want?

There are thousands of restaurants in and around Shinjuku.

It depends on what you really want to eat.

Tokyo is the largest metropolitan area in the world, and way too much additional information needed to give you a good answer. What do you want to eat? Where do you want to eat? What's your price limit? How much Japanese can you speak? Some of the best places to eat are in little hole-in-the-wall shops away from tourist areas, so no English menus would be available.