Over time, I've noticed some patterns in non-believers, reasons why they can't find God. If any one (or more) of these things applies to you, then you WILL NOT find God.
Reason #1: Not Looking in God's Direction
Therefore say to them, Thus declares the Lord of hosts: Return to me, says the Lord of hosts, and I will return to you, says the Lord of hosts.
Notice what has to happen first here. You have to first return to God, and the Bible gives a clear pattern on how to do this. You need faith and repentance. If you are trying to find God by some other means, then chances are, you're not going to find God.
Reason #2: Make Up Your Own god
Another reason people can't find God is because they make up their own god, or what they think God should be. I'm not necessarily talking about the flying spaghetti monster here. I don't think anyone is seriously out there trying to find the flying spaghetti monster. What I mean by "making up your own god" is this. Some people, I've noticed, want god to say, "Do whatever you want, with no consequences," or they're looking for a god that will give them whatever they want, on their demand. Or they're looking for the god that will make their lives perfect right now, by giving them this or that. Of course, these gods don't exist, and people that pursue these false gods often become atheists.
Reason #3: Pride
Pride is perhaps the biggest reason someone is unable to find God. All of the reasons here can relate back to a pride issue. 1 Peter 5:6 says to humble yourself and God will exalt you. Pride is the opposite of being humble. God asks that you humble yourself, confess and repent from your sins, and receive Christ into your heart. However, God resists the proud (James 4:6).
Other people I've noticed, will claim that they're looking for God, then proceed to deny anything and everything related to God. This is not an issue about evidence, for there are many reasons to trust the Bible. Denying anything and everything related to God is an issue of pride. Sometimes, people think that they're so smart, they don't need God in their life. Again, this is pride.
God is waiting for you with open arms for you to return to Him, just like in the parable of the prodigal son (Luke 15:11-32). But if you read the parable, you will notice that the prodigal son first admitted to his errors before returning to the father. Likewise, you need to take that first step in God's direction (Zechariah 1:3).
Reason #4: Hard-Heartedness
This is an extension of the pride issue, but there's one distinction I want to make here. Hard-heartedness can also be a case in which you know the truth, admit to the truth, and refuse to obey God. In the book of Exodus, there were multiple occasions which Pharaoh admitted that he was wrong, and God was right, and then still refused to obey God and let the Israelites go worship God. Pharaoh kept wanting to put stipulations on it, such as, "some of you can go" or "you can go, but don't take any cattle with you." This is not obedience to God and it certainly isn't humbling yourself.
Reason #5: Issue with Authority
I'm not just talking about an issue with obeying God's authority, but also earthly authorities. The Bible tells us that you are to respect the authority of those over you, because all authority comes from God. (of course, there would be an exception if the authority tells you to do something that would be a sin.) If you have problems obeying and respecting your earthly authorities, whether it's a parent, teacher, employer, public lawmaker, etc., how then would you be able to respect and obey the heavenly authority of God?