IN JUST FIVE EASY STEPS you too can slip, with passable dignity, into an evening of the good life in a Presidential Suite at the new Regent Hotel in Washington. Sure you can. Just follow these directions:

STEP 1 -- Have $1,200 handy.

Yes. The dignity starts here. And "start" is the correct term: $1,200, a fairly standard rate among Washington's finest hotel suites, pays primarily for one night's lodging in one of the Regent's two Presidential Suites, both nearly identical and both occupying the choice front-and-center position of the Regent's top two floors -- just below the distinctive rooftop dome of the city's newest (and certainly prettiest) European- style luxury hotel. Of course, this $1,200 doesn't include meals, liquor, phone charges, theater tickets or limo service, but it does include plenty.

In any case, if $1,200 is no problem -- and it wasn't for such recent Presidential Suite occupants as Michael Jackson, Adnan Khashoggi or Queen Noor -- you may now move on to:

STEP 2 -- Bring all the clothing you have ever owned in your entire lifetime (unless you are Michael Jackson, in which case bring the last two months' worth).

If you bring less, you will waste the closet space -- eight freestanding floor-to-ceiling cabinets, two armoires, two walk- ins -- available in a Presidential Suite. As well as all those removable wooden suit/skirt hangers, the leather-and-wood clothes brushes, the handmade muslin laundry bags, the same-day cleaning service and the 24-hour valet.

Do not bring a bathrobe (they're plush white terrycloth and already hanging in the bathroom), but do bring lots of shoes; if you leave any shoes in the armoires, they will be polished when housekeeping comes in to turn down your bed. (At which time they also leave a homemade chocolate truffle, a fresh orchid and a check-off breakfast menu you should hang on your doorknob by 2 a.m. if you'd rather be awakened by pastries and tea than the digital clock-radio on every nightstand.)

STEP 3 -- Bring a pianist.

There's a beautiful, shamefully well-tuned Yamaha baby grand in the parlor. And the pianist can stay in the third bedroom -- which is optional (the suite is $950 without it) and also has a separate entrance from the hallway. (Perfect for nannies, personal secretaries, children, Secret Service agents, etc.)

As for the parlor itself, let's just say it's spacious enough to dwarf a baby grand. Near (but not too near) the piano is a genuine woodburning fireplace, with its marble and beveled- glass mantle, which faces a large beige sofa (which matches the plush, non-synthetic, mauve carpet over otherwise oak floors) and three matching chairs around a smoked-glass coffee table the size of your bathroom at home. Behind the seating group is a semicircle of windows and a balcony overlooking the corner of 24th and M. The dining room table (marble top, brass bottom) sits in a windowed alcove off the parlor.

STEP 4 -- Do not go into the bathroom.

There is so much stuff to try in here, you'd never leave -- at least not before you owed another $1,200. There are three full baths in the three-bedroom suite (not including the powder room off the parlor) -- all champagne-colored Portuguese marble, floor to ceiling (as is every bath in the 265-room Regent). They all have whirlpool baths, wall phones, a speaker connected to the nearest TV, bidets, glass-enclosed showers (with Swiss-made fixtures which, like a good butler, remember water temperatures from one bath to the next) and sinks set in dark Italian marble. Plus a hairdryer, emery boards, a wicker makeup stool and clothes hamper, cotton balls, Q-tips and fresh-cut flowers. Enough to make you forget why you came in.

STEP 5 -- If you need assistance, please dial operator.

Or perhaps consult the international dialing directory in your bedroom desk; the Regent has direct overseas dialing. Or dial room service (open 24 hours), or the concierge, or the Executive Business Center downstairs (word processing, typing, dictation, Telex, notary public, paralegal assistance, open 8 a.m. to 8 p.m.). Or dial two at once; the desk phone in the bedroom has two lines and a hold button.

Or don't call anyone. After all, each bedroom and the parlor have a 19-inch Zenith with wireless remote and cable channels (so this is where you go for cable TV in the District). And there's the complimentary Chinese tea and fresh fruit that arrived when you did. And downstairs there are two restaurants and a plush, airy lounge (the Promenade; Ron Smith on the piano nightly) overlooking a gorgeous central courtyard, where the Count Basie Orchestra played at last month's official opening. Besides that, if you're staying in the Presidential Suite at the Regent, you really shouldn't have to call anybody.

They're supposed to call you.

THE REGENT -- Okay, so forget the Presidential Suite; say you'd like a night in an ordinary (to misuse the word) Regent room. The least costly deal: $118for two people arriving Friday or Saturday for a one-night stay. You still getthe tea and seasonal fruit platter and marble bath, but leave the pianist and the firewood at home. The Regent is at 2350 M Street NW, opposite a large hole in the ground soon to be a Hyatt luxury-suite hotel that will also help keep your complexion a nice deep green. Call 429-0100.