Just general tips on how to improve? That depends. What's your skill level? Do you have all your tech skills down? (Shffling and teching basically) If not, work on that. If you have all the down, then I think waddle dashing would be the best thing to work on specific to DDD. If you have both of those down to a science, then just more playing will give you more experience, and that's mainly what improves you. Learning matchups and playing other characters to expand your knowledge doesn't hurt either!
Also, even if your getting your butt whooped, play play play. And not just against your brother, because then you'll get in a rut and only play towards his playstyle. Play all your friends who will, go to your local tournaments, all that good jazz.
Whew! Yeah, I think that's it
