There are several reasons that your graphics, strokes, particles, etc. look patched onto your video and not the seamless gorgeousness that you require.
The first thing that comes to my mind is that your video quality may not be of the most excellent standard. It may be a bit blurry, noisy, and/or washed out, so the crisp graphics would look startlingly sharp on top of it. The best solution for this would be to get better video… Barring that then you could try to match its blurriness and noise on your graphics.
Also if your graphics are too white, too red, or too anything they’ll look out of place. Try going for more subtle looks. Try making some more organic motion too. That might help.
Consider the design. Sometimes poor design just looks bad. Put some thought into the typography, the colour scheme, the timings…all of it. Sometimes something as little as changing a font or colour can make a world of difference.
Without actually seeing what you’re talking about I can’t help much more. Let me know if my piddly little attempt has actually assited you!
– The Great Szalam
(The ‘Great’ stands for ‘Not So Great)
No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.