There's no principle of the Bible that works in isolation. Every of the biblical principles have their accompaniments. There are certain actions which must follow the biblical principle. For instance, the Bible teaches us to sow. Anyone who does not sow will not reap. There can't be harvest without sowing. The Bible says that as long as the earth remaineth, seed time and harvest shall not cease.
We can get what we want from God when we pray to Him. That is what the Bible teaches us. The Bible says ask and you shall receive. They that ask do receive. Anyone who wants to receive must know how to ask.
The question now is: Is only praying alone sufficient to give us what we want? Because every one of God's promises has conditions, it can't work that way. We must have to understand that when we pray, we must have faith. We must believe that God is able to do what we are asking of Him.
Another thing is that our faith must be backed up with work. We must work. If we are not working, the prayers won't be answered. So, praying alone is not enough, we must add work to our faith.