Before rushing to draw floor plans and choose fixtures, step back and determine exactly what you want and need in a new bathroom. You probably already have general ideas, but the more thorough and specific you can be from the outset, the more satisfying the final results will be.
Start by taking stock of your present bathroom. Consider everything from surface materials to more fundamental issues such as layout and location. Perhaps new flooring, wall coverings, countertops, cabinetry, or fixtures would do the trick. Or maybe you'll need to rearrange the layout of an existing bathroom, add onto it, or create an entirely new one.
Sometimes a bathroom doesn't work well because it has too much space. This happens most often in houses that were built before indoor plumbing. When the outdoor privy came indoors, it often was placed in a bedroom or some other space that doesn't function as an efficient bathroom. These old-fashioned bathrooms may contain all the essentials yet look and feel awkward in actual use.
Wants and needs must always be balanced against the budgetary bottom line. If you're updating a bath to make the house more marketable, don't overdo it. You could lose money by overimproving (spending more than you can realistically hope to recover on resale) or by installing unconventional products or materials. If, on the other hand, you plan to live in your house for the next 10 years, indulge yourself a little.
By choosing, say, stock ceramic tile instead of specialty tile, you'll save money and retain a high resale value. Simple choices can save money that you can then spend on a feature you really want, such as a whirlpool tub, a marble vanity top, or deluxe shower hardware.