The upper portion of a conventional oven is the easy bit. The best way to keep it clean is to wipe up spills as soon as they happen. The only "cleaning" it requires little water. But if you spill something, right along side or a red hot item, do not try to wipe it up immediately unless you want a nasty burn - best to turn on the fan to remove the horrible burning smell and wait until the ring has cooled before cleaning. If you have that kind of components consisting of a coil with a kind of the bottom of the dish, you periodically to clean the element. This can be done very easily by lining a dish-like thing that usually sits in the cavity below the element with aluminum foil (it also has the advantage that elements are better: aluminum reflects heat back into bottom of the pan where you want it.
The rest on top of an oven can be cleaned easily enough with the help of a little baking soda and a damp cloth. If you have any stubborn bits that are more difficult to remove, dousing them in water to soften them enough to remove. Baking soda will have to use a little more liberal, if you need to clean the grease splatters (which will put a lid over the pan while frying bacon ???). Enjo cloths - the special green grease to remove it - is great for work, and shift stubborn old piece of fat, even baking soda will not remove, as the writer has to deal cleaning up after his late and very negligent Grandmother.
You sometimes come across flat stove tops and covered with a glass-cum-mica surface. It is theoretically easier to clean, but manufacturers prefer to use "real" commercial oven cleaners and protectors, and a kind of scraper to remove the burn thing gunk. And it starts resemble the surface of the moon, if you spill sugar in it, while dense or caramel. If you leave one of them, or if you want, you can just use plain old water and / or an Enjo cloth rather than the fancy cleaners.
The inside of a microwave oven is easier, and all you have to do is wipe it down with baking soda and a damp cloth. The glass dishes below can remove and wash with your dishes - in the sink or dishwasher, as you prefer. To clean the really tough dirt inside a microwave oven - and to make the interior smell nicer - put a bowl of water under the microwave oven and drop half a lemon in it (or a slice of lemon if you're stingy like me). Zap water for several minutes so it all boils steam. Keep the door closed and let steam to get to work loose bits off. Wipe down. Really miserly people can remove the lemon.
Smears out of the microwave oven easily cleaned with a little vinegar. This is great for getting the glass shining.
The inside of a furnace is hell, and most people turn to the appalling chemical sprays when the time comes to clean inside the oven. This may be a minor one hell if you line the bottom with aluminum foil to catch the splatters (remove and replace the foil when it gets grubby), and if you cook smart and cover anything that is likely to drip, splatter, spit or swish while inside the oven. And you can clean the rest with natural cleaners. The first natural cleaning products to use water - put a cake tin about a third full of water and turn on the oven on high until water boils away. After you get out of yeast. Put a lot of yeast wall and bottom of the oven and let it sit for a bit before getting the scrubbing. This technique requires lots of elbow grease and lots of wipes, so you can probably skip going to the gym in the oven cleaning day. Enjo wipes also help.
The frame can be cleaned by smearing each step in a paste of baking soda and water, then wrapping everything in tin foil. Dip the wrapped and inserted racks in a bath of hot water and leave it for about ten minutes. The aluminum and baking powder will react to remove the gunk.