Some of the Pilgrims pray to graves when they travel to Medina and make Dua to the Prophet. This is not right according to the Islamic conventions.
Stroking of graves for the blessings (Barakah) is not acceptable.
Make Dua to Allah only.
The intention to visit Medina should be visiting the mosque, Masjid An- Nabawi which is known as the mosque of the Prophet.
You must be performing Ihram while you pass the Miqat. If you land on Jeddah and have plan to go to Mecca straight away to perform Umrah then make sure that you are in the state of Ihram already.
Don't forget to carry your Ihram towel along with you if you travel by air to Jeddah.
Women are allowed to wear whatever they like but that should be permitted by the laws of Islam.
The journey to Hajj is dedicated to Allah only. So, taking your own picture to show it later to others is contradictory to the meaning of Hajj.
Women who are in their menses should already be in the state of Ihram while they pass the Miqat. They should take regular shower and do Talibiyah like others.
According to the Islamic norms no one should uncover his/her right shoulder until he or she reaches the intended destination, i.e. Kabah and begin Tawaf. It was the time when the messenger of Allah, the Prophet, had uncovered his right shoulder.
If it is dirty then you should change the Ihram towel.
Don't get into the state of Ihram if you are only wearing the towel.
It is not right to shave your beard during Ihram (follow this before and after Ihram as well).
Wear a sandal while walking but in case it is not available with you then wear anything and walk until you manage to get a sandal.
Start the state of Ihram from anywhere. It is not important to be at Kabah while you start Ihram.
Concentrate on your statement while making Talibiyah: Labbayk Allahumma Labbayk.
Don't wear any attire which is stitched and is made with different pieces of clothes.
Take a bath with odorless soap and pilgrims can comb their hair as the wives of the Prophet used to do that during Ihram.
It is not necessary to shout out loud to let the world know about your intentions when you begin Tawaf.
If crowd doesn't allow you to touch the black stone then leave it, because it is not mandatory. Just face the stone and utter Allahu Akbar.
If interested then touch the Yemeni corner. Do not kiss it.
Don't worship the holy black stone.
Don't follow any book other than Quran to make Dua. It is not important to make dua every time you circumambulate the Kabah.
Make dua by yourself. Don't include yourself in the group of shouting people.
The Prophet only touched the Kabah and the Yemeni corner. So, don't try to wipe the Kabah walls.
Don't ever hurt anyone, especially when you are going to kiss the black stone.
Make sure that you don't face your hand to the Yemeni corner while you say Allahu Akbar. It is done only for the Black Stone.
Do not shove or harm anyone during Tawaf.
Do not turn your backside to the Kabah. Kabah should be there at your left hand side.
Avoid standing at the line of the Black Stone for long time. Try to move on.
Do not stretch 2 Rak'ah of Tawaf for long time.
Dua Maqam doesn't exist in Sunnah.
It is preferred not to have Wudu during Sa'i.
It is not needed to climb up to the peak of Safa and Marwah.
Take rest if tired.
You can also take a break after Tawaf and before Sa'I as well.
It is not needed to jog always in between Safa and Marwah. Only do it within the green lights.
Women are not required to run between the green lights.
No specific dua is there which you should utter during the Sa'i.
Make dua and raise your hand as the Prophet did on Safa.
Do not let others know about your intentions by shouting loudly before Sa'i.
Shaving or Trimming:
Shave your head completely.
If you wish to trim then trim from all sides of your head.
Ihram shouldn't be taken off until you are totally shaved or trimmed.
Do not shave your beard.
In Mina, Arafah, and Muzdalifah:
Confirm whether you are located inside or outside the border of the holy site.
Just try to reserve the place according to your needs. Don't occupy a place to sleep.
Pray at correct time in Mina.
Do not waste time in useless chats.
Spend the eighth night at Mina according to the Sunnah of the Prophet. Many skip this and go to Arafah straight away.
Don't shove anyone in the crowd.
It is not wajib to visit Mt. of mercy in Arafah.
Do not wipe the sands and rocks of the holy mountain, Mt. Rahmah, for Barakah (blessings).
If you wish then you can pray Dhuhr and Asr in your tent with your own group but it is not mandatory to pray in the mosque of Arafah (Masjid Namira).
Before Maghrib, it is not right to leave Arafah.
Women should avoid crowds, like in Masjid Namira.
Face Qiblah instead of facing Mt. Rahmah on Arafah when you make dua.
Realize that the time of Arafah is not the same as any other day. Devote yourself completely in the divinity after knowing the significance and essence of it.
Reach at Muzdalifah before praying Maghrib and Isha. If you feel that you would reach there at mid night then it is better to pray on your way to Muzdalifrah.
Rest only after you reach at Muzdalifah. Make sure that you are at Muzdalifah before taking rest.
The Prophet slept as soon as he had completed the Maghrib and Isha in Muzdalifah. So, pilgrims should follow the Prophet's footsteps as well.
Continue Talibiyah throughout the whole process.
In stoning the Jamarat:
The Jamarat is not devil. Pilgrims who think that have misconception about Jamarat. According to Allah it is recommended to glorify Allah by saying Allahu Akbar each time a stone is thrown to Jamarat.
Do not wash stones.
Sunnah doesn't allow pilgrims to throw big rocks, woods or sandals.
Do not hurt anyone and don't push others.
Do not say Bismillah while you are throwing the pebble.
Throw the stones discretely.
You can make dua after the first and second Jamarat.
Do not throw the Jamarat before the actual time.
Targets should be hit in proper sequence (smallest to largest).
Allow anyone else to throw the pebble on behalg of you only if you are unable to throw.
If someone else is throwing the pebbles for you then you are not required to collect the stones and return it back to the thrower.
Count the pebbles. It should be exactly seven.
In Tawaf Al-Wada' (Farewell Tawaf):
Some people wrongly attempt the final Jamarat after Tawaf-Al-Wada.
Do not walk in large groups during Tawaf as this can hurt others.
It is mandatory to spend the 10th and 11th night (not days) at Mina.
You have to leave Mecca after Tawaf-Al-Wada; otherwise you have to repeat the process of Tawaf-Al-Wada once again.
As long as you are out of Mecca (may be on your way), you can take your lunch or do anything else but it is obligatory to do these after Tawaf-Al-Wada.
Visiting Medina is not necessary during Hajj.
Do not clean or kiss any wall for getting blessings (Barakah).
Do not disturb the serenity by raising your voice in the proximity of the Prophet's grave.
Tawaf around the Prophet's grave is not required.
Ihram is not necessary to enter into Medina.
Dua should be made to Allah only.
If necessary then pray to Allah and ask him to allow his Prophet to intercede for you on the day of Judgement.
Do not shout at the nearby places of the grave during Dua. Face Qiblah.
Adding Hajji to your name after getting back home is not right.
Only Allah can ask his Prophet to intercede for you.
A final note:
Some of the pilgrims are not aware of these facts. They do not even know that what they are doing is Haram or incorrect. So, it is important to know and understand the essence of the journey to Hajj.
Another group of people is ignorant but they have the ability to learn. This group of people is unaware of the true facts due to their carelessness. Allah doesn't like their laziness.
Another batch of people knows their mistakes but still continues to do it to follow their culture or to misguide others. Misguiding others is definitely wrong.