To go on a date, enter a club or restaurant and find the pink heartnode. Tap it to open your contact list.
You will only be able to bring love interests (which are represented by a heart next to their name) and real-life contacts on dates. Select who you wish to date from the contact list. In the date location, tap on your date’s speech bubble and select "Start Date".
Please note that the romantic progress you make in your game will not affect you dates/friends’ games and vice-versa.