A few reasons, could be anything. Could be a) problem with the upward communication (God hearing), or problem with the downlink communication (us hearing).
Praying to the wrong God..prayers is to the Father, through Jesus Christ, and by the Holy Spirit. Prayer involves all three. The Spirit is our link to the Son and the Father, Jesus is our link to the Father. God's real name is YHWH or Yahweh, Jesus's real name is Yeshuah, or Jesus Christ of Nazareth. Don't pray to Jesus Christ of New York, that's the wrong Jesus.
Praying in the wrong way:
Prayer must be to the right person: Prayer for needs, wants, desires, to the Father, prayer to Jesus Christ for the same, prayer to the Holy Spirit for everpresent help and comfort.
Praying for the wrong things. Don't need to ask for things we already have. Don't need to ask for things God promised not to give. Don't need to pray about things when the answer is right before our eyes, in these cases the usefulness of prayer is not to receive an answer from God, but to realise the help and answer He has already provided.
Assuming God has heard, he has promised to answer. Four types of answers, yes, no, maybe, or wait.
This very statement is in indication of the start of doubt, and lack of persistance:
"I'm just wondering since none of my ever seem to get answered... "
Instead of thinking like this, start thanking and praising God that He has answered. Your statement is from a position of doubt, a thankful heart is from a position of victory and faith.
Even if they don't seem to be answered, believe that they are and will be, regardless. Believe you have already received the answer, even if it doesn't seem like you have:
Mar 11:24ThereforeIsayuntoyou,What things soeveryedesire,whenyepray,believethatyereceivethem,andyeshallhavethem.
This is what this verse means, believe that you have received it from the very moment you ask. Even Jesus's prayers weren't answered immediately, take courage in that. Forget about "if it be thy will" prayers, they sometimes do more harm than good. When you pray for something good that you know God wants to give you, don't doubt His will, goodness, love or good intentions.
Prayer must be from the heart. Not mind, the heart. The heart is in your belly, in your chest, in your innermost being. Not the fleeting thoughts and ponders of the mind. It's best to avoid use of the mind, just pray with your innermost groans and sighs, with your emotions and feelings, just pray whatever comes out of your mouth first. Pray before you think, rather than think before you pray, and let the Holy Spirit take over your words so that whatever you pray will be from the Spirit, and then you will be praying the perfect prayer in accordance with the Father's will.
The standard of way of praying is to think with your mind, and pray whatever you are thinking. But the mind is not supposed to be at the forefront, it's the middle man. When something is on your heart, that is put there by the Spirit who helps us to pray, you pray what is in your heart, that goes to your mind, and then your mind speaks to God what comes from the heart. Not, receive what is in your mind, and try and bypass your heart straight to God. That results in wishy-washy earthly, fleshly, soulish, touchy-feely prayers of no effect. Pray in the Spirit, and then the prayers are much more effective. Let the mind take a backseat.