If you are talking about increasing your friendship with some people then yes you need to give them good comments, be polite with them. Respect their privacy. And post good things and tag them to share your post.
Don't do too much friend request in a day. You can be banned for 15 days by Facebook if you will do too much friend request in a day.
Make your reliable and clear image on Facebook. Post interested and attractive content. Also join friends form other social networking sites. And don't send lot's off friend request.
depending on what kind of friends you want, you can join some "add me" groups and post there once per day and see requests coming in you can also ask people in there for friendship most of them accept instantly. just don't over-do it.
Don't send too much friend request to unknown person in a day. other wise you will get banned you account for 7days, 15 days or 30 days. so send that person request who accept your friends request.