What should I follow to get closer to Allah?

When we say we are striving to be better Muslims, what we are saying is, striving to become more beloved to Allah and that Allah will love us more. The basis of love is the obedience to what Allah has commanded, as Allah said, 

Say, [O Muhammad], "If you should love Allah, and then follow me, [so] Allah will love you and forgive you, your sins. And Allah is Forgiving and Merciful." [1]

Allah said to Prophet Muhammad (ﷺ) to tell the believers that if you love Allah, if you want to get closer to Allah, then follow the Prophet (ﷺ) and Allah will love you. We have to love Prophet Muhammad (ﷺ) to obtain the love of Allah. Prophet Muhammad (ﷺ) said, compulsory duties are the first that we are supposed to do. Allah confirmed that here for us. This is where we have to start from; we have to start with compulsory duties. We should start from the obligatory duties and not from voluntary act. The reason is that, obligatory duties are the foundations; if foundations are not strong then whatever else we are doing is a waste of time. Because, Allah will first, foremost ask us about our obligatory duties.

You will find people who chose a deviant path. Under the title they choose, they will neglect the foundation and they will bring a series of voluntary acts that you can do. That will be many, many things which will make you busy, but it will take you further away from Allah, rather than closer to Him. You cannot put voluntary acts before obligatory acts.

Example:  When time of prayer comes, we should prioritize compulsory prayers over the Sunnah prayers.  Sunnah is voluntary, it is additional. The compulsory takes precedence over the voluntary.

The Messenger of Allah (ﷺ) said: “Allah Most High says, ‘He who is hostile to a friend (Wali) of Mine I declare war against him. My slave approaches Me with nothing more beloved to Me than what I have made obligatory for him, and My slave keeps drawing nearer to Me with voluntary works until I love him. And when I love him, I am his hearing with which he hears, his sight with which he sees, his hand with which he seizes, and his foot with which he walks. If he asks Me, I will surely give to him, and if he seeks refuge in Me, I will surely protect him.’”[2]

References: 

[1] Surah al-Imran, 3:31

[2]  Sahih Bukhari, 8:76:509