As Christians we are not selfish in asking others to pray for us nor should we feel that we are imposing upon our brothers and sisters in Christ to ask them to pray for us. Our triumphs are their triumphs and when we prosper the whole body of Christ prospers, therefore when we ask others to pray for us we are actually helping them by 1) strengthening the body of which they are a member and 2) bringing a blessing unto them by helping a fellow brother/sister in need. Therefore please be bold in asking others to pray for you.
Some of us ask saints and angels to pray for them (this is something I have done in the past although I know it may be frowned upon in many Protestant denominations). I do believe many of the most effective prayers are from those who are closest to us, be they friends, family members or our neighbors. However, we should also not hesitate to reach out further and ask for prayers in online forums, blogs or even to reach out to professional prayer warriors such as those in monasteries or convents (which I have done). Aside from Jesus Christ, who knows our hearts completely, we are probably our greatest advocate because we are the most interested in our development and growth and so we must be bold in asking others to pray on our behalf, which I feel is part of working out our salvation.
Paul frequently asked various churches to pray for him and all of the saints and so we should follow his example and garner up as many advocates on our behalf as we can.