Oooo Marvy! Now here's a book for all you divine creatures out there. Why be a stay-at-home when you can play at home. . . or anywhere. And ""anyone can do it"" says San Francisco's answer to Truman Capote. After all little Patsy Lou came from nowhere Oklahoma and now look--television, radio, personal appearances, charity ball consultant who has bashed Frank Sinatra and just keeps the social swirl in a mad uproar by throwing little soirees like that just ultimate in groovy Mod party a year ago. Of course it helps to have been a model (just try stuffing a dumpy you into a sleek hostess gown). And it also helps to be a blithe spirit--one major point--don't worry about money. And Miss Montandon obviously doesn't, there always seem to be some provident ""beaus"" handy. Or ""Party Buddies,"" ideally a male neuter. But if you have that urge, this how-to expertise includes everything but the alka-seltzer. From making up the guest list-lots of young, a dash of old, a sprinkle of extroverts, an exhibitionist or two, don't forget some good listeners, etc. to menus, types of have-n-balls-Mexican fiestas etc. to ladies' luncheons to picnics and on and on. Miss Montandon even outfits you with a diet, personal make-up checklist and exercise chart to get you in the mood. No party poopers please.