One of the easiest things you can do while filming is work on better stabilization. This may be as simple as purchasing a nice tripod but could be as ‘cool’ as looking into user friendly gimbal systems for moving stabilization. So many cool ones out there like this one from DJI.
To an extent even lower end footage can look quite professional if proper grading is applied. Better to shoot as high quality as you can of course but with proper practice you can grade (add color/contrast/etc) to your image to make it both appealing and dramatic.
Your soundtrack is crucial. You have the ability to put a level of emotion into your video (whether to make it fun or dramatic or whatever) but that depends on getting the right sound and music in there! There are so many great options for good music now (Musicbed, SongFreedom, Art-list.io, etc) but shop it out and have fun!
The other part of your soundtrack is mixing it all whether the spoken word, music, or ambient sound. This too can be super fun as you play with ‘feel’, rhythm, and fancier tools like compressors and EQ’s. Correcting bad audio is part of this but also getting to enhance the good stuff to make it truly superb.
Sometimes the only difference between a not-so-great edit and a real pro feeling one is just adding or subtracting a frame or 2 in your clips. Spacing and adding ‘padding’ can make a huge difference (way more than viewers realize!)
Oh and of course in your editing (as we like to say a lot) DELETE the needless content. Keep the story the main priority — anything that doesn’t contribute: CUT! Your viewers will love you for it.