"Setting up intermediaries between oneself and Allah, making supplication to them, asking their intercession, and placing one's trust in them."

Any practicing Muslim, who prays five times a day. He or she should realize the first chapter of the Qur'an (surah fatiah) verse 5:

You (Alone) we worship, and You (Alone) we ask for help (for each and everything). (1:5)

Every human being is a sinner. And no one reaches to Allah in order to tell him what to do, regardless how pious he may be. There is a open challenge mentioned in many places throughout the Qur'an. 

Allâh! Lâ ilâha illa Huwa (none has the right to be worshipped but He), the Ever Living, the One Who sustains and protects all that exists. Neither slumber, nor sleep overtake Him. To Him belongs whatever is in the heavens and whatever is on earth. Who is he that can intercede with Him except with His Permission? He knows what happens to them (His creatures) in this world, and what will happen to them in the Hereafter . And they will never compass anything of His Knowledge except that which He wills. His Kursî^[] extends over the heavens and the earth, and He feels no fatigue in guarding and preserving them. And He is the Most High, the Most Great. [This Verse 2:255 is called Ayat-ul-Kursî.] (2:255)

"Calling upon the dead, asking them for help,"

When someone dies, he or she, regardless who they are, or how pious they may be, each and every human being worries for there own deeds committed during there lifetimes. If someone is calling upon them, and saying that the person is coming and helping, for example, through a dream. Or asking help from that person, then he or she has committed disbelief (kufr). No one has any right to insult Allah, after Allah has certified that he ALONE is our provider. So when we ask through someone, instead of asking only from Allah, then there is no difference between us and the people of the scripture (Jews and Christians). For example, some ask seek intercession through people who are considered to be by them, pious. This is our test, the way we think, it will happen. And it will look like it was done through them, but it is not, we are just going deeper and deeper in sin. Another example, the Hindu would go and buy a ten dollar statue, and would ask from it a million, and many of them are millionaires, because the way they thought, that would happen accordingly. There belief is poor, so the way we ask it will happen. That statue is helpeless, and cannot do anything, but there obedience towards Satan (Shaytan), so Allah allows them to be misguided.

Lets say, if one is stuck in a problem, and that person only begs and cries to Allah, and seeks his repentance then, Allah's mercy is bestowed upon that person, and his problem would be solved. No one would feel pain for anyone else, whoever is the victim of that sickness. 

One should seek repentance from Allah, whatever was committed in the past, because, this is a major sin. 

"or offering them gifts or sacrifices is all shirk. [Qur'aan 2:165 & 255, 5:72, 30:52, 39:44]." 

There are examples of some who go to a so called "pious" person, and offers him a gift, to make him happy, because if he is happy then Allah would be and he will make a better prayer, that is what they are under the impression of, this action takes one far away from Islam, because that makes one more careless, and that person thinks that he is under that so called "pious" individual, and that he would take him to heaven, and defend him on the day of Judgment. 

And some get there hopes fulfilled through graves, and this is really only an attraction from Satan, which is misguiding people. Some go to graves and put really expensive sheets, carved with gold wires. And leave lots of food, money, and most of those things go to the management of the grave. And this is also a really major sin, and this has no basis whatsoever in Islam, this is a very great sin, and disbelief (kufr).