Q:

How difficult is it to create a clone?

In the Star Wars universe, the concept of clones is not new.  Obi-wan, when he learns of them, is somewhat versed in the basics of cloning and able to ask relevant, on-topic questions.  This suggests that clones are not unheard of, and some of the techniques of cloning are taught - on a theoretical level - as part of the basic education of Jedi (and possibly regular Republic citizens as well).
During the war (according to the EU) Spaari cylinders were used to grow clones in around 1 year - these are highly illegal post-Clone War, and were apparently rare during it.
All of this speaks to cloning being relatively easy, yet the galaxy seems to lack some fairly clear off-shoots of this technology, such as replacement limbs/organs.  In the real world, such things are potentially viable within the next several decades, despite the fact that our cloning technology is ages behind that which the Kaminoans demonstrate.
This makes me believe that cloning is more a specialist tool, an area which doesn't get much study or that wasn't seen as viable for whatever reason.
Is it that difficult for them to make clones?  Or did the entire galaxy just turn a blind eye on the potential medical benefits?

A:

In Heir to the Empire, by Timothy Zahn, set after Episode 6, the Empire finds some Spaarti cylinders and makes some more clones. It seems the technology on how to construct the Spaarti cylinders has been "lost", as the destruction of the newly found cylinders stopped their cloning efforts.
Also, in Episode 2, Dexter Jettster (the fat alien guy at the diner) says that Kaminoans are "cloners, damn good ones". That implies that there are cloners who are not as good. Maybe other cloned humans/aliens are low quality, i.e. intelligence lower than droids. Also in Heir to the Empire, the cloned Dark Jedi Joruus C'baoth was insane, possibly as a result of the cloning process. Maybe this makes it not cost-effective to clone sentients compared with manufacturing droids.

A:

One could theorize that they were applying a "slippery slope" mentality.  They may theorize that it is a very small leap from cloning a hand--such as might be needed by Anakin or Luke--to cloning an entire being.  The technology would be the same.  Only the scale would be different.  Therefore, as bureaucrats the universe over think the same way, one might safely assume that in order to ensure that a full clone is never created that they would outlaw all technology related to clones and cloning, no matter the medical repercussions.  
It can be closely analogized to stem-cell research in the US in recent years.  Many argued about the slippery slope and where does one draw the line.  Therefore most, if not all, stem-cell research was banned entirely. 

A:

It's never explained in-Universe explicitly why cloning was not more widespread; but it was used by a variety of species.
From: http://starwars.wikia.com/wiki/Cloning

Notable races that made use of cloning technology include:
Kaminoans, Polis Massans, Khommites, Ithorians, Lurrians, Verpine, Columi, Yuuzhan Vong, Arkanian Microtechnologies

Moreover, the technology was widely known, as evidenced by a Telos Holocron quote from one of its gartekeepers, Darth Sidious:

"As practically everyone knows, cloning is the science of taking a cell from a living organism, duplicating the genetic code, and growing the cell into an exact duplicate of the cell donor." (Source: Jedi vs. Sith: The Essential Guide to the Force)

