Each day brings with it new opportunities to share your faith, that's why it's so important to be ready. Ready to give an answer to those who have questions about your hope in Christ, ready to stand firm where some might challenge your faith and ready to share the good news where others are ready to receive.
Instead, you must worship Christ as Lord of your life. And if someone asks about your hope as a believer, always be ready to explain it. (1 Peter 3:15, NLT)
Preach the word of God. Be prepared, whether the time is favorable or not... (2 Timothy's 4:2a, NLT)
As believers, we need to know the word. We need to know what we believe and be secure in that truth. If you don't really believe what God says, why should anyone else watching or listening to you believe? Our job is not to create opportunities, but to be ready when they arise. The worst thing is to find yourself in a situation where the Holy Ghost cannot use you simply because you're ill-equipped. He will tell you what to say and bring truths to your remembrance; however, if you have never read nor heard what God says on a matter, what is there to remember?
There is something special about being a ready and willing tool for the Lord. It's great to be willing, but to also be ready makes you useful at the time of opportunity.