The majority of Japanese women aged 18-23 are very immature and naive, as in, a lower maturity level compared to women the same age in western countries. Most are interested in simple conversation (movies, celebrities, taking purikura…) and most are not interested in serious romantic relationships because they are not capable of understanding such things. They will be more into fun and just hanging out. Their English level will be very low and they will mostly work in shops, cafes, restaurants and the like.
The more mature women of this age group are more international -those who have lived or extensively traveled abroad, so their English level will also be fairly high if not fluent and their personalities will be more Western. These will also be the types who will work in offices.
The main problem is that women are general split into two types:
they will either be more immature, shy, and have little to no English skills
or they will be more mature, act more Western and have a higher English level
To find a mix of the two will be quite difficult since they are very rare, so when first looking for girls, it’s best to weigh what’s more important for you.
I recommend staying away from the usual “gaijin” places (Roppongi, Shibuya, Kabukicho, and Shinjuku) since most of the girls who go there are either pretty dirty or just looking for men with money, plus there are a lot of foreign "bad apples" who go there, so you don’t want to be labeled the same. Foreign men in these areas are also the prime targets for expensive hostess clubs and similar.
Some of the areas that will work best for you would be the following list. They are the same names as the train stations and the majority can be accessed via Yamanote train line.
Mostly women working in offices. There are many cute, intelligent girls with class and many will know at least some English if not fluent. There are a few really good malls and fantastic restaurants in this area, so chatting up some of the ladies after work or during lunch works best. One of the best places would be in Oazo Marunouchi since there’s a big Maruzen bookstore that many of them like to spend time in.
More international areas. There are sophisticated women, more trendy and have their own money or business or they are University students. Many will speak fluent English and be more comfortable with non-Japanese people. There are a lot of opportunities to chat with the ladies in these two areas. Another one that’s a prime spot to chat with ladies is in Daikanyama (about 10-15minute walk from Ebisu station). Daikanyama has a lot of trendy shops, cafes and restaurants.
A little more international with women working at business as office ladies. Some will know English but not most. There are a few different shopping areas near the stations where most of the ladies like to hang around and shop after work. Shimbashi and Shiodome station has a place called Caretta, which has a lot of restaurants, cafes and a few shops that people hang out in. The large outdoor area has seating dotted around, so chatting up one of the ladies there is a good option.
More business areas, fairly international and many of the office ladies will know some amount of English. There are two main exits to Shinagawa station, Takanawa Exit is towards the Prince Hotel and lots of shopping and restaurants. The Konan Exit leads to the main business buildings but there are still a few options available in the Intercity buildings since there are a few shops, cafes and restaurants dotted around there as well.
High class area with many women who are very trendy, wealthy and a bit more snobbish. These ladies will be comfortable around an international crowd; however they will generally have their guard up in this area, so trying to pick them up on the street or near shops may not work well. Try to catch them in bookstores or if they are alone in cafes.
The majority of Japanese women are used to people trying to pick them up, so being obvious may immediately bring their guard up. Start with simple conversations and try to use some Japanese because this will make you seem more vulnerable and make them more relaxed. Many women, even the ones who understand English pretty well are still shy to speak it in front of native English speakers, so some Japanese will certainly put them at ease.
One of the easiest ways to start talking to ladies in Tokyo is by politely asking questions about the area or asking for directions. You will notice many people tilt their heads down to appear more submissive when speaking to someone, so this tactic may work for you, especially if the girls shy away very quickly.
Touch is a pretty big thing for many people in Japan (especially since there's a lot of inappropriate touching in Tokyo trains) so flirty touches that work with other women doesn't work as well with Japanese. Be gentle and patient for things like that.
The most important thing to do is really observe the girl's actions and expressions. Japanese women are generally more uncomfortable in social situations without friends and the Japanese in general have subtle expressions and reactions to Western people, so if she's uncomfortable, it may not be as obvious as with other women.
As for thoughts of gifts, this is entirely up to you. Whenever you feel like giving something to a girl, do so but of course, try not to go big the first time around. The type of gift depends on the woman’s personality. If you notice that she has a lot of cutesy key chains or phone accessories, she will certainly appreciate gifts like that. If she only has designer things, chances are she would like even a small gift from a designer that could set you back some money.
One of the best things that you can give a woman in Tokyo is something sweet. They love their little decorative cakes and pastries, so if you have seen her eating a sweet on one of your dates, giving her a beautiful decorative cake or macaroons works like a charm. (The best places for cakes are Ginza Aoyama, Omotesando and the basement area of malls in Marunouchi, Shinjuku (Takashimaya, Marui, Issetan) and Ebisu station (upper level of the station).