There was a similar thread on this subject a few years ago that might help here.
That said, the best and most foolproof way is to engage OOCly for connections and to come up with premises that force your character to interact with others.
For example, someone accuses your character of a crime, which forces your character to respond to the information and engage. Or, your character needs a particular thing and the other person's character is the only one who has it.
Regular walk-ups and RP interactions can work but generally don't pan out for characters who are withdrawn or reserved unless there are other characters present who are willing and able to force your character to interact. Once you have a few connections going then you can gradually start to rely on being approached rather than doing the approaching, but otherwise the solutions are either A). figure out a way for your character to seek information or initiate, B). form OOC connections and arrange for RP in such a way that is conducive to both characters, or C). find or create a plot or storyline that will place external pressure on your character to interact.
That said, the best and most foolproof way is to engage OOCly for connections and to come up with premises that force your character to interact with others.
For example, someone accuses your character of a crime, which forces your character to respond to the information and engage. Or, your character needs a particular thing and the other person's character is the only one who has it.
Regular walk-ups and RP interactions can work but generally don't pan out for characters who are withdrawn or reserved unless there are other characters present who are willing and able to force your character to interact. Once you have a few connections going then you can gradually start to rely on being approached rather than doing the approaching, but otherwise the solutions are either A). figure out a way for your character to seek information or initiate, B). form OOC connections and arrange for RP in such a way that is conducive to both characters, or C). find or create a plot or storyline that will place external pressure on your character to interact.