Do you have any chemistry background at all? I'll assume you know a bit about molecules and chemical equations.
The easiest method in my opinion is:
Potassium Ferrocyanide (anhydrous) + Sodium Metal == Sodium Cyanide + Potassium Cyanide + Iron
In chemical equation form:
K4[Fe(CN)6] + 2Na
→ 4KCN + 2NaCN + Fe
You can easily buy both the Potassium Ferrocyanide and Sodum metal at local Chemical Suppliers, or even on eBay.
You heat the mix of potassium ferrocyanide and sodium metal at around 300-350°C, until after it completely melts, then you'll have the products (4KCN + 2NaCN + Fe). Then (after cooling it down ofc) you'll then need some sort of filtration to separate the Iron (Fe) from the cyanide.
Here's a video showing the whole ordeal, including exact quantities of each substance:
(this video used to be up on Youtube, but was taken down along with a bunch of other content considered "dangerous")
The Potassium Ferrocyanide you use in this reaction needs to be in its anhydrous form. However I believe you can only buy Potassium Ferrocyanide it its "trihydrate" form ( K4[Fe(CN)6]·3H2O ). To convert the trihydrate into anhydrous, put the powder into an oven at 150°C for a couple of hours, occasionally shuffling the powder around.
This method and all the other methods under the sun for synthesizing cyanide are discussed at length on chemistry forums. I recommend specially
http://www.sciencemadness.org/talk/ .Use the search function there to find discussions of all the methods.
I personally lost interest in Cyanide after finding Sanctioned Suicide and going through all the discussions on how painful it is CTB'ing this way.
EDIT: To neutralize cyanide, which you'll probably get on your gloves and other things, the best option is to immerse all the things touched by cyanide into a concentrated solution of sodium hypochlorite.