If you like music, you can ignore the musical theory, as it will come to you as you make your songs

Hey there~

[This is gunna be a long message, so just skip to the bottom if you want the tl;dr]

I'm a dj/producer and i've been making music for a few years now.
if you wanna make good dubstep, the first thing you need to know is: music theory. if you know more about music theory, you'll be able to make much more interesting and complex tracks.
The second thing you need is a DAW [digital audio workspace/workstation]. There are many daw's out there [Live, Reason, Logic, FLStudio, Reaper, Sonar, Garage Band, etc] and the very best one is...... all of them. There is no best daw. They all have pros and cons, and it's usage depends on you. My suggestion is to go out and try demos and look at reviews, and find whichever one you feel most comfortable with. I use Ableton Live, and they have a 30 day trial demo, plus they just released Live 9, so i'd suggest starting there, then maybe trying out fl studio or reason or something.
Third thing you need: sound design. knowing how to make the sound you want is key. you dont wanna be stuck using presets forever, your music will all sound the same, boring, and people will know you're using presets.

Which leads to my next suggestion: plugins. Plugins are.. well.. plugins for your daw. there are effect plugins, synth plugins, drum machine plugins, sequencer plugins, etc etc. There are alot of free ones online, or you could buy/torrent the big expensive ones.

Now, say you've got your daw and some plugins and you've gone to music school and gotten everything together. you still need to know how to make DUBSTEP <3

Now, i wont bore you with the actually pretty interesting history of dubstep, or give you a lengthy tutorial, but i would suggest looking into it's history and roots, and looking up tutorials.

PLEASE PLEASE PLEASE remember that dubstep is a subgenre, and has MANY different styles and fusion genres. dont get stuck in one style. which reminds me, ALWAYS ALWAYS ALWAYS experiment! trying new things and expanding your horizon is so important, especially in music.

Anyways, a really basic/simple tutorial on dubstep:

the beat is usually syncopated, and generally consists of kicks, hihats, and snares.
a more relaxed, calm dubstep track is usually 128 bpm, a more aggressive, "brostep" track is usually 140 bpm.
you're gunna want a lead, bass, drumline and fx. i might be forgetting something.. lol. but keep in mind that dubstep is about BASS. bring that bassline up! go for wobbles or a straight bass. but please.. dont use all that middy crap [i mean literally mid register, not midi lol]. use real sub bass. you can learn about layering and resampling later, lol.
anyways, im in school so i need to wrap this up.

The tl;dr version is: go download ableton live and try it out, if you dont like it, try some other daws. look up tutorials for dubstep on youtube and check the native instruments forums. torrent/buy FM8 and Massive. they're great for dubstep leads/basses [and everything else], but keep in mind you can use OTHER synths. EXPERIMENT! also buy a better laptop, you wont be able to do much on a macbook air.... get a macbook pro. uhh.. yeah. and just keep at it!!

if you want more help, email me at haycraftadam@gmail.com, all i do is make music and play minecraft so i have time to answer your questions, lol. good luck!

Also if your looking to make some filthy 8bit dubstep you want to get MilkyTracker its free but incredibly hard to use if you don't know what you are doing.

lotmomFl studio is probably the best for any music...

Thats a bold claim. FL is ok, but far far from being the best. Its ok for dubstep though.

Fl studio is probably the best for any music... if you know how to use it. i dont know how to use it but if you are willing to pay it is worth it

Logic.

I also use garageband and its pretty good (if you know how to use it)

I use Garageband on my MacBook!