Well, usually a houshold starts with 'like minded' individuals... You can simply start a household by announcing to your friends that you are starting a new houshold, and it's called <place name here>.

Depending on how you want the group to be, service household, drinking household, etc.. you should decide what format you want, then set your goals and go to it. It usually helps to develop and register a badge with your Kingdom so nobody can take your ideas for a household. Keep in mind, the larger your house gets, the more potshots you will take about your household 'taking over' blah blah blah.. if you remain steadfast and honorable, they will eventually die out and people will appreciate the house more. Just be ready for those kinds of issues, and try not to let them get to you.

As far as membership, you can opt for the 'open membership' (someone telling you they want in the house and you letting them)

or set up guidelines for prospective members ( members should not hit other members with halibuts, never spit on a member, be nice, eat pizza, etc)

Then the other way is to only pull in members you and your house have been watching, secretly and subversively approaching them like a secret cult, and telling them you've been watching them, and if they would be interested in joining the house. (This works best with a company of black hooded people surrounding them...J/K)

Some Houses try to snatch up newbies.. The households in my group wait at least 6-8 months before letting a newbie in simply because there is alot they should learn before deciding what household is right for them, if any.
There.. that's a little info on what I know.. bottom line is:
Just try to keep it fun, don't get TOO serious and the household 'should' run itself.

Hope that helps!

<disclaimer> Only my humble opinions. There are plenty out there on how to handle Households.