It is when I read scripture that I begin to praise. Things I hear that are spoken to me personally about what He is doing in and for me, for all the promises of God belong to you through Christ Jesus.
Or when I take a walk outside and find a tree, flower, clouds, things of nature that I love to look at, I thank Him for the beauty I see. Praise him for your eyes that can see.
Or when I think (as Lynn mentioned) of a moment of pleasure I had each day (even in a good bite of food), I begin to thank him for making what we eat so tasty - that I can chew and swallow and smell.
You mentioned playing the guitar - well, you don't even have to sing. Let your fingers just strum allowing the Holy Spirit to move them freely. Tell God that you are playing for Him. I do this on the piano. As you begin to just make a melody, sometimes the words about God just come. But if they don't, He loves to hear what your fingers can do. In the Psalm, David mentions to praise Him upon the instrument.
Find a list of the attributes of God - plenty on the web - and begin to praise him for each attribute one by one. While doing so, thank Him for any one of those attributes that you have seen him work in your life.
Your praise can be loud or quiet. It is yours.