I've found that, with a new oven, regular wipe overs with water and a cloth (usually the washing up water) is enough. If I make a huge mess with a particular dish I might sprinkle on a little bi-carb and spray a bit of vinegar for a scrub, followed by plenty of rinsing. And when the racks are gross, give them a scrub.
If your oven is in a bad way, buy some oven cleaning spray for a first clean. I've only used this stuff when leaving rental properties - and the oven has always been better when I leave than when I arrived! It will have instructions. I put old newspaper on the floor around the oven. Take out the oven racks, including any side rails (more on that later). Then spray the oven cleaner on the door and inside the oven, following the instructions. Then I come back the next day (following instructions) and clean out all that toxic mess.
For the racks, I fill the laundry sink with enough hot water to cover all the racks, then add in half a litre (1/4 gallon??) of cloudy ammonia. Come back the next day and the gunk scrubs off really nicely. Rinse in clean water and they will be nice and shiny. Then put your oven back together.
Once you have it all nice you can just wipe it out regularly (once it cools down after use. Perhaps get into a habit of wiping it out when washing up).