Stacking Beginners will try their best to avoid leaving any blots. This is not a good strategy especially at the early parts of the game when getting hit is not a big deal. You will gain more by setting up your position by slotting than any potential loss from getting hit early in the game.
Splitting A common mistake by beginners is neglecting the runners (those 2 checkers way back). Beginners will usually wait until they roll a double to move the back checkers up but doubles are rare and sometimes you can use them somewhere else so splitting the back checkers slotting for an advanced anchor is important early game strategy. You want to move those back checkers before your opponent has developed her position. The longer you wait the harder to escape. Also if you make an advanced anchor you have much more flexibility to take doubles, and attack your opponent with loose hits because you have a landing spot in case you get hit back.
When behind, don't race If you are already behind in the race, you don't want to race your opponent. Get an advanced anchor and hold back.
Doubling When you are starting out don't worry too much about the cube. Play single point games or short matches (3 pts). Cube handling requires an intuitive feel for how the game is going and this comes only with experience. The basics of cube is of course to remember your mandatory doubles when you are post crawford and basically try not to get hit with a doubled gammon. If the position looks gammonish and your opponent is 4 away, drop. Another basic cube concept to understand is the 25/75 rule. If you take when you have 25% chance to win or drop is the same. The math works out to break even even though it might seem that taking a double with only 25% chance is a terrible strategy, if you drop you do lose a point so dropping does cost you something. So for example of you play 4 games and dropped each time your opponent has 75% chance you lost 4 points. if take, you lost 3 games *2 cube which is 6 but you win 1 (25% of 4) and its doubles so worth 2 so you still out only 4 pts either way. Of course once you start playing at a high level, there is a lot more to it involving formulas that take match scores into consideration.
Doubling way late Often beginners will wait until they are certain to win before doubling. This is not a good strategy. First you lose the chance to double while your opponent has a take thereby losing the chance to win a doubled game. Next problem with this style of cube action is that each roll your opponent gets for free he is happy to take because he could roll big and catch up without any risk as he can drop anytime when you finally decide to double. So the thing to understand is that turning the cube is not always an aggressive move. It is sometimes a defensive play to prevent the opponent from getting a free roll.
Always fight for your golden point Dont ever give up your 5 pt without a fight. If your opponent slots that point always hit loose if necessary to knock them off there. You dont want to give up an advanced anchor and have that obstacle cramping your moves.
Analyze your games Use the free gnubg analysis software from https://www.gnu.org/software/gnubg/. You will be surprised at how many mistakes you make. Most mistakes will be obvious. Simply did not see that blot for miscounting the roll. Other positional errors may not be as obvious to understand. When starting out focus on the big blunders of which you will have plenty. They will be highlighed in red. If you run into a position where you dont understand why its a blunder, post the position here or at rec.games.backgammon and someone will be happy to give you an explanation. You can also repeat play out the position and see how it turns out. Gnubg does also have a rollout feature that does that. A rollout can sometimes reverse the decision of the analyzer but those are rare. Most of the time if you get a blunder that is exactly what it is. A huge mistakes that kills your match winning chances.
Step by step instructions how to analyze with gnubg - viewtopic.php?f=19&t=152
Read up Search google for backgammon articles. Getting insight into how expert players think is a great learning opportunity.
Watch BG videos of the pros playing with commentary. Like this one .. viewtopic.php?f=31&t=292
Play Play Play Every game you play, you learn something. Dont focus on winning or losing. Whether you won or lost is not important. If you lost a match and your analysis comes up "expert" you are a winner. You can still enjoy a match even if you lost. It is a good opportunity to YELL at the bot to release some stress energy.
Each match is an adventure. Enjoy the journey that the dice takes you. It's only a game. Have fun with it.