There is a myth about studying endgames for beginners in that you should study them the most out of any aspect of the game.
Understand that you need to study the endgame, but don't make it the highest priority. You need to become 'comfortable' at each stage of the game. Perfect endgame play does you no good if you get slaughtered in the opening consistently, or don't understand the basics of good defense in the middlegame and get mated or drop mucho material from poor tactical play..
I would recommend studying only those endgames that are the most frequent.
1) Rook Endings
2) Bishop vs. Knight
3) Pawn endings
I would not waste *significant* time on any other endings at first as a beginner because the frequency of them appearing in practical play is comparitively low. Get a basic book on endgame play that explains the basic positional aspects of each kind. Play the computer in a bunch of these endings. Using Chessbase, you can search for a practically unlimited amount of endgame positions you can play out for practice. Keep the endgame book open in front of you so you can reference the ideas of what you are trying to accomplish in each category of endgame.
For Openings, you need to make some decisions and stick to it for a few months to see how it works for you.
Determine what openings you like to play, taking into account the complexity of the opening. As a beginner, I would recommend something along the lines of the Caro-Kann (Karpov Pet) as black against 1.e4, and the Slav agains Q-pawn openings. Both these openings tend to avoid pawn structure weaknesses, are solid, and are not too explosive. But, this is just a preference.
Go over a ton of games quickly. You are just trying to get a feel for what types of positions in the middlegame you end up with and what types of endgames come about. Pay attention. If you find you do not like what you see at this stage, CHANGE YOUR OPENING.
Once past this stage, examine well-annotated master games, preferably those that explain the strategic goals behind the opening.
Do this for a few months. Once you feel you understand the ideas behind the opening, only then do *might* venture into the realm of Opening Manuals if you got cash to burn. The only one I would buy is Nunn's Chess Openings.
Whatever you pick, stick to it for at least 100 games.
MOST IMPORTANT: Analyze your game afterwords. and try to get a better player (Cat A at least) to go over the game with you at some point, or if not possible, use a chess computer. Fix your opening errors. If your opponent made an opening error, and you did not punish him for it, discover the correct play via computer or reference or better player. Even post to the site for advice.
Get Organized. Database your games. http://www.chessbase.com
Middlegame improvement requires you to pay attention to the types of positions you get in your games from your selection of openings. Does your opening tend to end up with an Isolated Center Pawn? Perhaps a minority attack is frequent? Locked Center? If so, read chapters out of strategy books that are specific to the subjects and go over your games intensly where these situations arise. You can improve quickly woith a great deal of understanding by using this method. You will also help your pattern recognition skills because you will be playing similar positions in the middlegame from the same opening.
Tactics! Tactics! Tactics!
You cannot study tactics and combinational play enough. It is the first and foremost cause of losses in lower rated players games.
Study. Play. Apply what you learn. analyze mistakes. Again...
Reassess your play every few months. If you are losing games with a particular opening choice, either hit the grindstone and figure out what is going wrong, or dump it and try something different.
From this, you can see that your opening choice determines largely the strategic elements that will reoccur in your games, as well as the types of endings you will get.
READ REASSESS YOUR CHESS, AMATEUR'S MIND and REASSESS YOUR CHESS WORKBOOK.
These books will drill into you useful habits of assessing a position. There are reasons these books are so popular - they WORK!
Hope this helps,