To easily control water and lava, you will need a bucket. A bucket is easy to get, but chances are you will need a lot of them to effectively use them.
To get a bucket you will need three iron ingots, which can be found by mining iron ore with a stone pickaxe and smelting it in a furnace. To craft a bucket you will need to place the three ingots on your workbench in a “U” formation.
With a bucket you can collect and place water and lava. This is important because these two substances have many uses. For example, if water hits lava the two combine into obsidian or cobblestone (depending on if the water hits a source block or running lava). Both substances can be used to make a moat to protect against creepers, especially lava since it also qualifies as a light source. Lava can be used to make artificial landmarks more visible. Water can be used to make elevators. Lava can be used to make an incinerator. Water can be used to make a rivers for fast boat transportation. Lava can be used as the best furnace fuel in the game. Water can be used to douse yourself if you get set on fire. Lava can be used as a weapon against enemies.
As you can see, buckets are an incredibly useful tool, but you will need a large number of them if you wish to carry enough supplies to do everything you need to do. I usually carry at least five with me in case I need to reroute a bunch of water or quickly solidify a bunch of lava so I can cross. Also, since lava can be hard to come by sometimes, it’s wise to carry several buckets of it around with you when you’re on the surface where water is abundant… or just use a mcpe cheat to get all the items in minecraft!
One of the most spectacular uses of water I have seen, this is a building idea, was a gigantic water slide that reached from the top of the map and dropped down into a gigantic cavern at the bottom of the map that must have taken ages to mine out and fill with water.
Another building idea that might be fun to do would be to make a lava fall that feeds into a “factory.” Having the lava nearby would make it easy to get furnace fuel and the lava stream would make it so you would need substantially fewer torches. If you guys are interested in playing minecraft check out this guide by watching this video: how to get minecraft for free!