When one becomes convinced and has strong belief that Islam is the true religion ordained by Allah Almighty for all human beings, then he should go ahead and accept Islam without any delay.
The basic beliefs one is required to accept while entering the fold of Islam are as following:
1) God is One. He has neither a partner, nor a son or daughter. He is One in the true sense of the word that has no room for the concept of trinity, or for any other form of camouflage monotheism or a disguised polytheism.
2) The Holy Prophet Muhammad (Allah bless him & give him peace) is the last Messenger of Allah after whom no messenger or prophet of Allah (in any sense of the word) will come.
3) The Holy Qur'an is the last of the divine books revealed upon the blessed Messenger of Allah (Allah bless him & give him peace), and all its contents are true.
4) The life in the Hereafter (after death) is eternal, where one will face the fate of his good and evil deeds.
5) All the teachings of the Qur’an and the Messenger of Allah (Allah bless him & give him peace) in absolute and unambiguous terms are true and acceptable.
When an individual accepts these fundamental beliefs of Islam from the depth of his heart, and rejects those beliefs of his former faith that contradict Islamic beliefs, then he will be considered a Muslim.
As far as the verbal acceptance is concerned, the majority (jumhur) of the scholars of Islamic creed (aqidah) are of the position that verbal confession is a condition in order for one to be called a Muslim in this world, and on which judgments are passed, such as: Marrying, inheriting, being buried in a Muslim graveyard, etc…
Since having a belief in the heart is a hidden thing that must have a sign, therefore, whosoever believes with his heart (tasdiq bil qalb) and does not confess with his tongue (iqrar bil lisan) is considered a believer with Allah Almighty, but not according to the judgments of this world
(See: Sa’d al-Din al-Taftazani on the creed of Najm al-Din al-Nasafi, P. 190, Dar al-Bayruti, Damascus).
Therefore, if you are convinced of the basic and essential beliefs of Islam, then you are already considered a believer according to Allah Almighty. However, for you to be considered a believer in this world, you must confess and express your beliefs by saying the Shahadah.
Conversion to Islam is very simple and has no particular procedure, like baptism, etc. It is not necessary that one seeks the mediation of a saint or priest, nor is it a pre-requisite to go to a mosque or to an institution for accepting Islam. One can accept Islam on his own. However, it is advisable to go to a learned Muslim (preferably a scholar) who can inform you about the basic beliefs of Islam and can teach you the concise and comprehensive words to express the acceptance of those beliefs.
Normally the following sentences are used for that purpose:
"I bear witness that there is no God but Allah, and I bear witness that Muhammad, (Allah bless him & give peace), is His servant and messenger."
"I have believed in Allah and His angels and His book (as they were originally revealed on His prophets) and in His messengers and in the Last Day and in the fact that all the good and bad destinies come from Allah and in being raised alive after death."
Therefore, you must hasten towards verbally accepting Islam. There are no conditions or pre-requisites for accepting Islam. This is the religion (deen) chosen by the Almighty, and is the only religion which will save one from eternal punishment in the Hereafter. Therefore, go ahead and convert to Islam at once, without any delay, hesitation or thoughts about the practical side of Islam.
Allah Most High says:
“The Religion by Allah is Islam” (Qur'an 3:19).
In another verse of the Holy Qur'an, Allah states:
“If anyone desires a religion other than Islam, Never will it be accepted of him; and in the Hereafter he will be in the ranks of those who have lost” ( Qur'an 3:85).