There’s always space for yet another armor tutorial, right? (ﾉ´ヮ´)ﾉ*:･ﾟ✧
Note that the armor I drew would be worn around 15th century, the more into the future the less and less components knight’s armor had (i. e. in early 14th century instead of greaves a knight would wear long boots only; in 12th century knights didn’t wear plate breastplates and instead a chain mail only). Also the design of armor pattern changed by year and was different in every country (i.e. in eastern Europe armors, while still looking European, were heavily influenced by Turkey). so just make sure you always do research whenever drawing an armor. And one more thing to keep in mind is that armors were expensive, knights wearing a full plate armor weren’t an often sight.
Some links that may be useful:
Armour Archive (I strongly suggest to browse its forum, there is no country or period of which armor wouldn’t be discussed)
Therion Arms (armorer’s page; each accessory is photographed in big resolution and several time so it’s a nice page to use as reference for drawing)
Revival Clothing (another store, but both with medieval clothing and armors; I suggest to read the articles, they’re often supported with pictures)