Check your reel to ensure the spool is filled to the lip with new or at least good quality undamaged monofil? Clean and lubricate necessary
Check line and replace if necessary, check to make sure your reels brake blocks are of the correct size in relation to lure weight and free from oil.
Clean, lubricate and ensure you have free movement of the spool. Check line to backing to ensure the splice is of good condition, remake if necessary. Ensure the line is clean & undamaged.
Lures, flys & hooks:
Check each hook for rust or barb damage. Anything that has been bent is weakened & should be discarded and replaced.
Get rid of short `out point` hooks as more fish are lost on these than landed.
Hopefully your waders have been stored correctly during the off season to prevent unnecessary damage.
Check the rings for grooving or other damage, check each sections joints & apply a little beeswax to carbon joints, also make sure the reel fitting rings move freely & clean if required, vaseline may be applied if wanted.
To bring the rods appearance back to like new, scrub the cork with a nail brush and washing up liquid & wipe it down with a damp cloth inspecting for any damage at the same time.