It is hard to see the signs of loneliness, especially when someone seems so upbeat and happy. An easy way to help someone overcome being lonely is to just treat ALL of your friends and family as if they might be lonely. Checking up on your friends and family for a few minutes out of each week might seem like a big deal at times to do, but you may never know how rewarding your kindness towards them may go. In all you do, do unto others as you would do for/to yourself.
Some of the loneliest people reach out to you by being the best person towards you.