When you're learning a foreign language, they'll tell you that fifteen minutes every day is better that two hours on Sunday. It's that periodic repetition that keeps the ball in the air which does the trick.
Golf is the same way. If you can practice fifteen minutes a day, you can keep your game in tune even if you can't play.
Putt across the carpet. Step up to each stroke like it's a putt on the green--go through your whole routine. Practice three- and four-footers by rolling the ball over a tin can lid. Practice 30-footers in the same way, using a pillow for a backstop. The important thing here is that in making your 30-foot stroke, you hit the ball on the sweet spot and still roll the ball over the lid.
Get a carpet remnant and chip off that with plastic balls into the pillow you used for approach putts. Ball first, ground second. Rotate through all your chipping clubs over a period of days.
Hang a mattress pad or a blanket over a curtain rod in front of one of your windows and hit pitches into it (use plastic balls, please, and hit off a carpet remnant to save wear and tear on your flooring.)
Full swing? You can swing under an 8-foot ceiling with a 7-iron or less, but for a longer, club, step outside. If you have a back yard, you can hit plastic balls into a net or against that mattress pad. If you're an apartment dweller, well, just swing. Before very swing, go through your entire pre-swing routine.
Just do something, every day.