If you just want to give souvenirs to your friends or someone that's not really close to you, I recommend that you get chocolates!! But be careful!! Many people in Japan say that American candies are too sweet so I don't recommend getting Hershey's. My friends and coworkers at my part time job liked candies like the ones above so I recommend getting these.
If you want to get little fancy, I recommend stuff from Bath & Body Works. Their hand soaps can be pricey so I recommend getting either hand cream or hand sanitizer because I'll be really cheap if you buy like 5 at a time. Last time I got hand sanitizer so this time I got hand cream this time which was $3.50 plus tax.
If you want to get really fancy, (or a gift usually to someone you know really well or helped you alot ) I recommend getting COACH. I mean, you don't have to get them like a purse but mirrors or keychains will do good!! (People in Japan loves keychains!!) COACH is really popular in Japan and my friend told me that they are very expensive!!!!! Here, if you buy it online, you can get it for very cheap price!! I got these from outlet for about $20!!
Here are some things I usually get for souvenirs and I hope this will help you! Let me know if you have any questions!! :)