Getting a broadway ticket in NYC is a bit complicated and here is the guide.

Step 1: Try to learn theatre(s) map you are interested before buying anything. 

As a rule of thumb, center orchestra seats (i.e. on lower level) are first choice. Some do not like first few rows because they are too close to the stage. Then choose for more central seats on left and right orchestra seats if possible (e.g. left orchestra seat number 1 is more central than number 1. Same thing, right orchestra seat 2 is better than let say, 10). Orchestra seats are generally good till they are too far away and under mezzanine (i.e. upper level, 2nd floor). One reviewer said up to orchestra row "N" is still "nice." Again check the map of specific map of theatre of interested. If it's a small one, row "N" could be 2nd last row or something.

If you can not get good orchestra seat (or out of your budget), let's try upper level (i.e. mezzanine). Central, first few rows of mezzanine can be as expensive as orchestra seats.  Value seats are front rows of left and right mezzanine. E.g. left mezzanine row D or E 1 could be as good as central mezzanine seat but could be a lot cheaper.

Lastly, least expensive seats are orchestra seats under mezzanine where you can not see action higher up on the stage (if your show has two stories setting etc), too lateral seats on both floors. Sometimes those seats are sold as "partially obstructed" view -- so please remember that "catch", "warning" words. 

 Step 2: If you are a student, stop ----> buy "student rush ticket" around $20 at box office of the theatre. You do not deserve to spend hours at discount ticket booths. Same deal to people who are fortunately enough to spend full ticket price, i.e. around $130-150 for good orchestra seats and front mezzanine seats or pay full price around $69-90 for side seats. You can buy full price tickets at box office of each theatre (if you already decided which one you want) or stop by at Concierge of your hotel or at visitor center at time square.

Step 3: If you are looking for discount tickets, you could either try "tkts" booths at different locations or buy online at sites like "broadwaybox.com." Discussions about pros and cons are as follows:

Tkts booths is a great option if you do not mind waiting in line for a hour or so. Tkts charge least amount of processing fee, like $4/per ticket and you can also download "tkts" application on your smart phone (both androids and iphones) and you will see 30-50% discount of most broadway and off broadway shows. Again go back to step 1, try to refresh your memory with theatre map and decide whether it is worth paying 50% discount for a good central orchestra seats or a less expensive side seat. Tkts is suitable for those who do not mind waiting in line, buying for a big crowds (one can stay in line and other can enjoy walking around time square!) and you get tickets right away. Main disadvantage is there is no guarantee that your favorite show is available for discount on that day (although you could predict most of the time).

Online discount sites are useful if you want to make sure that you got tickets of your favorite broadway tickets before traveling to NYC and obviously no waiting in line.  Some sites are charging as high as $15 processing fee per ticket and in addition to that they might charge $15 processing fee. In order to receive your tickets, someone needs to be at home to sign for Fedex. Otherwise, you will be picking up your tickets at some restaurants or shop near broadway/time square. So please do your math and after adding all fees and cost, make a final comparasion with full price.

Step 4: Enjoy. Your ticket is in hand. Most theatres are small and there is no significant difference between most central seats and lateral seats. At least sound quality is the same.

Also refer to an excellent tripadvisor review on broadway ticket buying resources, details on tkts by previous reviewers.