Why do folks clasp their hands and bow their heads when praying? Is there a reason, other than humility, that we are taught to pray with bowed heads and clasped hands? Other religions, such as Judaism and Muslim – even with the variety of Pagan pantheons – raise their hands and lift their faces Heavenward.  Is it that most find doing so ‘odd’ or ‘strange’ – or is there more to it than just an outward appearance?
IDK about clasping hands, as I don't do it. I do know that we bow our head in respect for the one we are praying to, God. 

It is much the same in a legal case. When you approach a judge you address him differently than say a sales clerk. When you talk to the judge, your speech is more respectful as is your body language. When you talk casually to someone your mannerism change completely. 

When we do these things for God, we are showing regard for his position of authority. We are also showing that we are in subjection to our father.

The clasping of hands may be to show love  and encouragement for your brothers in the congregation. Hebrews 10:24-25:


  "24 And let us consider one another so as to incite to love and fine works, 25 not forsaking our meeting together, as some have the custom, but encouraging one another, and all the more so as you see the day drawing near".