1. 8lb leader is for after you know how to land em (& only if you HAVE to use it), 4 sure go to 10 lb & i would go to 12 & i know people will scream when i say this but, "unless you're fishing a smaller river & the water is shallow & real clear" 8 vs 10 vs 12 (ande or maxima grade line) is not going affect your bite all that much but will improve your catch ratio ... why hook a fish you stand a good chance of losing on light line? better to perhaps (& that's a big perhaps) miss a bite or two but get the ones you hook...
2. you have to believe you will land it
3. if you're hooking them in fast (more that 3,200 cfm) current, after you hook them, loosen your drag enough so that if they want to run they can & WALK THEM DOWNSTREAM, do not stop walking them downstream (keep rod tip pointed in the direction you're walking) until they are in the frog water (real calm stuff), trying to hold a fish in the current for even a few seconds is dangerous, trying to bring them upstream is suicide...
4. keep the line tight, loose line allows your weight to work the hook out
5. the size of your hook is determined by the size of your corky, the corky cannot be wider than the hook = the barb of your hook must always be just outside the diameter of the corky or you are not too likely to get good hook ups, if the barb is just wider than the corky (i.e. a # 2 hook for the smallest size corky & a # 1 (NOT 1/0) hook for the next size up corky you will be fine with 10 for 99 cent Mustad's (I have proven that for years)
6. don't use hooks you find on the river, don't use hooks you bent back into shape after pulling it out of a snag, every time u re-tie, use a new hook
7. check your entire leader when you get done tieing it & every 25 casts or so, pinch it with your fingers & slide down the full length, pay particular attention to just below the swivel, your weight, more often than not ends up hitting your leader during its travels down the river, denting it up, if you feel any thing at all suspicious, re-tie, constant leader vigilance (even when the bite isn't on) is a hassle but it is a necessary thing
finally, the biggest reason's i've lost fish & seen fish lost is drag too tight (holding the fish in the current)