For a first car generally you want a standard, default, reliable and affordable car that will teach the new driver where things are supposed to be, where to look and how the car is meant to feel. Such is the same for a beginner acoustic guitarist. Ferraris are great but not the best for a learner driver. Just as buying a fancy looking acoustic with wild and whacky dimensions isn't the best choice for a learner guitarist.
The best general advice: A full sized, cutaway, steel stringed, acoustic guitar ranging in the $200 to $300 range. If the guitar comes with accessories, even better! A guitar tuner, a guitar stand, some picks and pack of extra steel-strings will set up a beginner acoustic guitarist very nicely. This will give a beginner the best fighting chance at learning quickly and with ease.
Best Shape For Beginners
A nice default design such as the "grand auditorium" shape is another term you can search for. This altogether will help the beginner understand and grow recognition for how most guitars will generally feel like when go from guitar to guitar.
Also a full-sized (4/4 / 40inch / 101cm / adult sized) guitar will be a great place to start for anyone over 12 years old. For players of a smaller size, a 38" guitar may be a better choice.
A cutaway design would also be recommended as reaching the higher-frets will be much harder and sometimes inaccessible for beginners. If you want to learn the entire fretboard, it would be best to have access to the entire fretboard.
Best Tone-wood For Beginners
I wouldn't focus too much on the tone quality of the guitar you purchase, as the tone-woods and shapes that generate these unique sounds can be out of the average beginner budget but also can be hard to hear the tone differences without any past reference point and/or experienced ears. Generally a linden basswood guitar will do just fine for a beginner guitar. A highly affordable and widely used wood with a very flat, balanced tone. Nothing special, but it doesn't need to be!
Best Strings For Beginners
Yes nylon strings are softer and easier to play with but ultimately can be a mistake. It can be quite a struggle to convert to from a nylon strings to a steel strings as a beginner. Quoted by many beginner guitarists, "Converting to steel was like learning guitar all over again". As they say no pain, no gain, the tougher steel strings - although may hurt a tad at the beginning - will help you grow the required calluses, finger strength and flexibility needed to progress. Another positive to steel strings is most guitars have them. So if you go to a friends house and there is a guitar, you can play it with ease without the conditioning of the softer nylon strings.
There are also all different types of steel strings you can get. But the one most suited for a beginner would be the light gauge. Sometimes referred to as normal light, bright tone or super light. A gauge around .011 to .050 is a good place to start.
Best Price For Beginners
Even though there really is no such thing as a beginner guitar. It is reasonable that a beginner would want to keep him or her investment as low as possible while still getting a good bang for your buck! The $200 - $300 range is a good price range to aim for. You'll get well made, long lasting guitar at this price without having to take out a loan. Any cheaper in most cases will sacrifice build quality. However, an exception is at pintagoguitarsandgear.com, they tend to have a great selection of guitars under $200 that are actually very well made and suitable for beginners.
Best Gear For Beginners
Tuners, capos, strings, stands, cases, picks, straps, amps, scratch plates, pickups, EQs... I could go on forever! All great tools for a variety of reasons, but which are the essentials?
As a beginner, the more the merrier but if you had to choose the most needed acoustic guitar accessories would probably be: a chromatic guitar tuner, guitar stand, some picks and a pack of extra steel strings.
Tuner
You cant play unless the guitar is tuned, so pick yourself up a chromatic tuner. Tuners will also help you learn the notes of the fretboard and train your ears correctly.
Stand
Protect your guitar and your walls with a guitar stand. When you're not playing, your guitar needs a place to call home and leaning her against a wall is just asking for chips, scratches and falls.
Picks
Picks AKA plectrums are something all beginners need to pluck the string and get a clean note.
Strings
And lets just face it, beginners don't have enough experience to know to treat the strings sometimes. And with some aggressive strumming or over tuning will come, a broken string. So it's very handy to have an extra pack of strings laying around in case the dreaded SNAP strikes... inevitably
So in summery, a normal guitar. Nothing too fancy, nothing too confusing... leave that for when you progress a little more. This doesn't mean you can't get a nice looking guitar. There are many beautiful guitars with abstract grains and extra little details that still fit all the criteria mentioned above. Here is a link to some great looking guitars at the beginners advantage. Ultimately, the goal is to train your brain, arms and fingers on how a guitar is meant to feel and sit on your lap. You do this right, and you'll find yourself rocking the world in no time!