New contemporary guide gives tips for easy entertaining at home; The Book of Entertaining at Home, by Maureen Mole. New York: Cornerstone Library. $5.95; Fancy Folds: the Art of Napkin Folding, by Linda Hetzer, illustrated by Robert Penny. New York: Hearst Books. $8.95.

Those who have trouble mustering the time, energy, or courage to give a party will find encouragement in a new guide. Friendly and readable, "The Book of Entertaining at Home" gives tips for elegant party-giving that will tempt even the busiest mother or career person.

First, Maureen Mole advises, take on only what you can comfortably handle. A successful party, she points out, does not depend on a gourmet menu or extravagant decorations but on learning howm to entertain. That involves finding the style of entertaining that suits you best -- cultivating the knack for serving food with finesse, creating inviting table settings, and making guests feel special and at ease.

For novices planning their first get- togethers, the book explains how to stage all types of parties from backyard gatherings to formal sit-down dinners. For those weak in the knees or the pocketbook, it discusses various kinds of co-op parties for sharing costs and planning.

Whatever type of party is chosen, the book emphasizes, advance preparation is a key element. Simple steps such as pretesting recipes and preparing dishes ahead help keep last minute worry and tasks to a minimum. For fail-safe planning and organization, the book offers this timetable:

* A month ahead: Draw up a guest list and send out or phone invitations. Decide on the menu, party theme, and table settings. Arrange for hired helpers if necessary.

* Two weeks before the party: Write an inventory checklist of all the items needed such as linens, tableware, serving utensils, and cheese boards. Buy, rent, or borrow anything that is not in hand.

* A week ahead: Write the shopping list and menu cards. Make place cards and send out reminder notes to follow up telephoned invitations.

* A few days before: Do the housecleaning and polish or wash necessary items. Do the food shopping and start the advanced cooking.

* The day before the party: Set the table, finish cooking, gather serving platters, utensils, and other equipment. Fill salt, pepper, and sugar containers. Rearrange furniture if needed. Tend to the decorations.

* The day of the party: Retouch cleaning and freshen up the bathroom with clean quest towels and new soap. Put the finishing touches on recipes, clear countertops, set out nonperishable foods. Rest.

What the schedule laks in spontaneity it makes up for in peace of mind.

Even with the best planning, however, unexpexted situations can crop up. For these minor dilemmas, there is a helpful section on how to deal diplomtically with guests. The book also includes a section on how to be a good guest yourself.

Since the table is one of the things first noticed at a party, it deserves special attention. "Fancy Folds: the Art of Napkin Folding" shows how to turn a useful article into a decorative asset. It provides step-by-step instructions for everything from simple folds to very complex versions requiring two napkins. Each step is numbered and coupled with a clear illustration. Historical notes about the different fol ds are also included.