Unable to identify and convert winning positions

There are two reasons
1) blunders
2) playing too fast: you end the first game with more time than you started with

You should always check your intended move is no blunder before you play it. A great help is to activate move confirmation in your profile: think about your move, play it, check it is no blunder, confirm
Most chess games are essentially decided by move 30. So use all your time before move 30 and finish the game on increment.

Thank you so much: I did not know I can switch on move confirmation. That will be a great help!
Yeah I had 8 minutes when I lost.. I'll try rectify that. Thanks

When you're up material simplify!!!

This is something stronger players use alot too. When youre up a piece and there are still 10 pieces on the board your advantage is less then when everything is traded and youre the only one with a piece. Just try and trade everything and you'll be fine.

I think you get overconfident in clearly winning positions, so remember to always stay concentrated and do not let your emotions take over. And something that probably you have heard a lot, always look for checks, captures, and threats from both sides. It is something basic but easy to forget!

You need to finish your development. In both of your games you have undeveloped pieces. You tend to press an attack. Once you get a small advantage, you should regroup and develop the rest of your pieces. One of the games is a full on queen rampage. A queen can't win a game without support from other pieces.

You seem to be losing both games to straightforward tactics.

If you do some puzzles, you will learn that many tactics start with a check.

Now ask yourself what the games would have looked like it you asked yourself each move:
Does my opponent have a check?!

It would not have been hard to prevent Qxf7+ in the first game, and even the final move in the last game (by moving any N)

You can't post in the forums yet. Play some games!