Your apartment should be prepared for the photos. Clean and tidy - the two main guidelines that you must do even before a personal or virtual tour of the house. Nobody wants to move into an untidy house, which can, additionally, tell a lot about the hygiene and the standards of the current owners. Plus, it may significantly lower the value of your real estate.
Be careful not to go to extremes either. Too perfect apartments may not make a great impression on prospective buyers, so you'll need to find a middle ground: the apartment you're selling should be cozy and inviting. Don't be too meticulous: buyers aren't looking for a living space that requires and awkward attention for cleanness at each square foot. You should be able to present a livable space to the interested parties.
The most important part of the process is taking the pictures. You don't need to buy professional-grade, expensive equipment, since you can create high quality images with your mobile phone as well. Nonetheless, you may invest in a more expensive camera if you take such shot often. There are some tricks that you need to know, however, if you want to go by the former method.
Your own photo-equipment vs. photographers
There are numerous devices that allow you to take pictures, so if you decide not to use a professional photographer, you can learn how to take pictures, too.
You can use the camera on your mobile device, or a DSLR machine. Whichever you decide to use, you need to be familiar with the functions of your device and know which settings are to be employed with each shot.
You can create images even with a mobile camera that will make the jaws of potential customers drop, not to mention using more professional equipment. The pictures you take will need to be sorted, and, if necessary, using an image editing tool, edited as well (if the lighting conditions were not favorable, for example.)
But, if you don't want to spend your time with taking pictures, find a photographer who takes and edits these images; both solutions are fine, and you can even ask the seller's opinion about it.
You need to pay close attention to the lighting conditions. This factor depends on the location of the apartment, so, if necessary, take the photos in different times of the day, where the lighting of a specific room is the most advantageous. Feel free to switch on the lights, even if there is daylight outside, if that improves the lighting conditions.
Take the pictures while standing on the doorstep of the room. Don't take photos of parallel walls, since it will create the illusion of a tighter space. So, if the room is smaller, it is a good idea to put some of the movable things away, making the room seem larger. Take multiple photos of the same subjects and sort out the best ones later. Don't share every inch of your apartment; make the potential buyers interested in your place so they would come and check it out personally (and later more likely to buy it).
When taking the photos, make sure that your hands aren't shaking. If necessary, invest in a tripod or find a point where you can point the camera to the subject without having to hold the equipment in front of you. You want to use only the best images, so no blurred images should go on display.
Note: don't forget to include the floorplan. It does not strictly belong to the photos category, but still, you should include them with the rest of the images. There are several services on the internet that allows you to make professional looking floorplans by providing the metrics of the apartment. Having looked at the plans, prospective clients will have an easier time imagining what the rooms are like in relation to each other.
Technologies today are available to create videos at home, from your own couch. You can make a video tour of the house, or a Virtual Reality content that places you at the scene - these are, however, are very expensive for sellers and buyers as well, so few people use it.
Videos about real-estates for sale is getting increasingly popular - displaying the rooms in the same sequence a visitor would tour the house, with minimal editing, highlighting the advantages of the house. The same rules apply as with taking pictures: pay attention to lighting conditions, camera angles, etc.
Most mobile phones can produce high quality videos, but taking the shots doesn't mean that you are done with your task - you need to gain experience, and practice the different tricks of video content creating. It is worth investing in a tripod, or other equipment (e.g.: lamps.)
You also need to take the necessary time to edit and cut the footage. If you decide to do this yourself, you'll need a video-editing program and, of course, lots and lots of patience along the way.
Drone videos have been gaining popularity for some time, but had been used mainly outdoors only. You can film with them inside; however, pay strict attention to controls. Any large areas or apartments with high interior will make such videos work.
Special modern solutions
There are other, ultramodern solutions that haven't been available for that long (for wider audiences), that may seem awkward for an average real-estate video and might not even be playable on most devices. You can use ultra-high definition videos (4K, 8K, etc.) that will allow you to show every inch of your house in great details.
The 360 degrees video / image technology is getting more popular, too, and these let you look around from a certain point, just like you would if you were standing at that spot. If you combine this with VR technology, you can even tour the house you're considering buying without leaving your apartment.