Linen quality will vary depending on the manufacturer - more expensive linen can be very forgiving with wear, but there are still many easy techniques to use for cleaning any linen upholstery, nomatter the quality. As usual, vacuuming should be done regularly and before any particularly large clean - this will keep particles out of the fabric!
If you have a particular stain on the fabric, begin by soaking up the excess fluid, and then spot clean by applying a small amount of distilled water and a white cloth (to prevent transfer of dyes). Mild soap can also be used for a tougher stain - but be sure to blot and not rub! Dry cleaning will also work superbly with linen furniture if done by a professional. One thing to keep in mind, however, is that excessive staining and cleaning will remove the protective layer most linens have been treated with over time.