So hard to give info on the web. It could do you no good or even make you take a few steps back. The site that helped me out the most when I first started was discgolfreview.com. Very good instructional articles. As for discs...how long have you been playing? and how far are you throwing at this time?
Check out the sites below, watch the discraft videos on their main site and maybe pickup the Feldberg/Climo video along with Scott Stokely's 3 disc set. If these things don't help you then nothing will.
are you throwing everything on the market or are you throwing where your game is at,at this time,something to be considered,maybe thats where your game is right now,maybe step down a disc and you might get some results,the big disc that come out on the course on a weekly basis arent made for everyone.and so are you throwing 250feet,or 550feet,hole distance is in feet in discgolf....its unclear in your post..its a progressive task getting distance
There are several things that most people do not seem to realize thay are NOOOOOOOOOOOT doing when they struggle with distance.
1. Are you throwing across your chest? i.e. You want the disc to come across your nipples, sorry ladies, it is what it is.
2. Are you reaching back far and turning your hips around as well? i.e. I reach back waaaay far and come through.
3. How's your snap?? I tell people to act like they are popping a towell on someone. To me it is a good visual.
4. Are you following through? You cant just grip it and rip it without a good follow through. Bring your arm around THROUGH your throw.
5. Is your run up in good timing with your release?? A good throw is a bang bang bang scenario. Run up, plant, pull!! and of course follow through.
My main thing seems to be a good follow through for added distance.
I would recommend speed 9 or 10 drivers that are a little understable. Beast, Surge, Valk, Avenger SS, Roadrunner/Sidewinder. Watch a lot of videos and relate to them on the course.