Do Paul and the other Apostles command the keeping of Kosher diet in Acts 15:29? If so, why do many ignore it? I realize there are many verses as well that state in the New Testament that nothing is to be considered unclean anymore, but that makes this verse stand out as particularly odd.
The forbidding of blood comes from before the time of Moses :

But flesh with the life thereof, the blood thereof, shall ye not eat.
Genesis 9:4 - KJV

After the Flood, in a new arrangement, flesh is given men to eat, but not blood. In a world now cleansed with water, flesh is made available :

... my flesh, which I will give for the life of the world
John 6:51 - KJV

Blood is not given to unrepentant mankind to consume. The blood of the everlasting covenant is received by faith, Hebrews 13:20.
So neither blood, nor things strangled (instead of having the throat cut and the blood drained out) are permitted to the gentiles. This is not because of Jewish practice, it is because the commandment of God to Noah pertains to everyone on earth until the end of time.
Meats offered to idols is a matter of fellowship with idols which Paul makes even clearer to the Corinthian believers in the eighth chapter of First Corinthians.
Again, it is not a matter of Jewish practice, or custom, it is a matter of contemporary fellowship with local idolatry.