For plastic plants and rock work, that's fine. For wood, you'll need to scrub a bit more--it grows into the wood, and simply removing the exterior growth sometimes doesn't make it go away for long. Sometimes bleaching the wood will work--but not always. If bleached, make sure to dechlorinate well.
I wouldn't remove the gravel--just use the siphon tube to pull up any solid wastes for it.
When cleaning the glass, make sure you either siphon up the cleared algae, or have it sucked into the filter that can then be cleaned out. If it's left to float around the tank, it will happily attach and start growing where it settles.
If you have live plants, some can be cleaned by dipping them in a bleach solution--there's a sticky posted in the Planted forum that details how to do this.
Keep in mind that doing this all at once will kill a significant amount of the bacteria that you want to keep. I'd spread it out over a few weeks.
