Feed them, have them talk to people, have them go to the bathroom and take showers/baths, make them have fun, make them comfortable and you should have happy sims..
Or you can do Ctrl + Shift + C and type in maxmotives
Chat with our AI personalities
You have to have The Sims 2 Happy Holiday Stuff pack installed.
Look at the answer where the question was is there a cheat to make my sim happy
talk to connor
Yes, and you can also celebrate New Year's Eve on Sims 2 Happy Holiday Stuff.
You can make your sims happy by maintaining their mood-metre or spawing the cheat gnome by pressing B,Z,Up,Down,B and then when you find the cheat gnome press minus,plus,Z,Z,A