
Remember that these are general guidelines, and although they'll show you some fairly generic arrangement ideas, there's no harm in following them. A "forum" argument you'll see frequently is that people don't want to use the same track structure as everybody else, they want to be more original than that. Which is a valid point, but frankly if you're struggling to get an arrangement down in the first place, it's basically irrelevant - like so many of the arts, you need to get the basics mastered first. Then when you can knock out a good, effective arrangement easily, you can start to vary it and make it more original...
Dubstep

Once you're into the drop, and your bassline is rolling, you need to manage your switch-ups. Deeper dubstep can sit in a groove for a long time, with perhaps a subtle change in bass patterns or sounds every 8 or 16 bars. More hyped, "filth" sounds change constantly; fills every 4 (or even 2) bars, changing the bass patches every few bars, bringing in new percussion every 8 bars and also perhaps using your main melodic theme (from the intro) for the last 2 bars of an 8 bar phrase.
After a 64 bar drop, an 8 or 16 bar breakdown will give your track time to breathe before the 2nd drop. This can be a reprise of the intro - bring the melodies back in, and perhaps use a buildup again, depending on how "hype" your tune needs to be. In the 2nd drop you should employ a different bass pattern or sound to keep the interest up. A 32 bar section here will suffice, before you move on to an outro of 16 bars or so - most dubstep DJs don't even let a track get this far before mixing out.
Hip-hop

Intros can be kept short; 8 bars will usually suffice, and outros can be equally short, even using a fadeout. One thing to consider is using the vocal hook or chorus from the outset; if it's a strong chorus people will want to hear it, and there are plenty of tracks out there that start with the chorus. The only really tricky part is the bridge; generally a simple way of treating this is to use a key-change. Then when you change key back to the original, it gives a great sense of momentum as you swing back into the track.
House

Breakdowns and buildups are not always necessary beyond having a breather from the main groove; if you're going for a classic US house sound, then simply dropping out the kick and some of the bass may work well. If, however, you're working on an electro house sound, then a big 16 or even 32 bar breakdown, complete with woosh noises, kick rolls and soaring riffs will be essential. See our recent article on buildups for more tips on that front. After the breakdown you can return to the original groove - gentle switchups are useful to keep the interest levels up, but introducing a whole new vibe isn't always necessary. A long, beat-driven outro of 16 or 32 bars will help DJs mix out of the tune.
So, if you're really stuck for arrangement ideas, just follow one of these simple guides. Once you've got a basic structure down you can tweak it away from the norm - but remember that no house or dubstep track ever got a bad review on the basis of it's unadventurous 32-bar intro! Keep things simple, and you'll be able to focus on the stuff that's really important - a good groove, strong melodies and a solid bassline. So no excuses - load up that idea that's been sitting in your DAW for weeks and get started....