Allen, I've noticed a certain recurring theme in your games.
Here are two positions you played:
In the first you played .. e6, in the second you played Bd2. Neither move necessarily a blunder at all, but I think they show a pattern you may want to consider.
In the second game, one of the most natural ideas for black in that position will be to play b4. Whether this is done of his own accord to continue his queenside play, or whether white provokes it with a4, it'll happen almost always. So what does that change about the position? And similarly for the first position, what does e6 change there? Here are both positions after certain modifications:
It's probably not difficult to see that they both create huge holes. In the first game e6 naturally creates huge holes on d6 and c6. And in the second b4 will create a 'partial hole' on c4. Of course holes are only a weakness if they can be exploited. So can they, and how?
In the first game, that hole can definitely be hugely exploited. Ne4 directly hits at both weaknesses simultaneously and black is already in alot of trouble. For instance after 1. Ne4 Nf5 (trying to cover the d6 hole) 2. Bg5 (attacking one of the holes) Qc7 3. Bxc6 dxc6 4. Bf6! (getting rid of the dark square defender further increasing the vulnerability of these holes) black is already strategically lost.
The second position is alot more subtle. What it has to do with is how would you now exploit your opponent's inevitable b4 advance; what weakness would you target? In this case it is the c4 square. A knight on that square would look incredibly eying all those juicy central dark squares. And what is the most direct route to get there? Nd2->Nc4. But you put your bishop on d2! And if you take this one step further. If black wants to shore up his weakness on c4, what will he play? He'll play d5 when suddenly the pawn on c5 becomes a weakness which a bishop on e3, for instance, would be immediately targetting.
In the second instance black could have hopped on this inaccuracy by immediately playing 1. Bd2 b4!! when your knight is more or less forced to the really terrible a4 square unless you want your pieces to all end up stepping on each other after Ne2. And your bishop isn't doing much besides taking up a useful maneuvering square and potentially getting in the way of your queen along the d file.
The point is pawns are the only pieces that can't go backwards. You really need to be really conservative when making moves that open up potential holes in your position. A move like e6 in the first position is going to make most strong players' eyes bleed. And similarly, you need to always consider what your opponent's most likely pawn moves will be - and how that can be exploited, and how it will impact your future development and plans. Or in this case, you actually gave him a chance to play a move he's probably going to play eventually regardless, but in a much more dangerous way.
Pawns are the one piece in this game where mistakes can't be undone, and your position is defined by your pawns. Devote some time to pawn play and your game will definitely see improvement.