To grind fletching from 70 to 90+, I recommend grinding on a few arrows to as high as you can go. Making a quiver of 70QL War arrows will provide better skill than making a quiver of 50QL war arrows. Sleep bonus helps a lot. Making quivers of 80QL war arrows will help the skill gain when your skill reaches around 80+. Spamming quivers of 50QL arrows is not recommended due to its slower skill gains. I personally prefer Maple War Arrows (for Grinding) ~ AAetius, Master Fletcher.
Thanks to [[Bulk storage bin]]s, you no longer need all 5 carpentry tools for fletching. Using all 5 tools, the Log always run out, as your other tools can be repaired and improved. This makes the Log the least desired tool for casting [[Wind of Ages]], [[Circle of Cunning]], or [[Blessings of the dark]]. Also, you can not improve an arrow that needs a log to be improved, if your log quality is lower than the quality of the arrow. Putting the arrows that need the log to be improved into a Bulk Storage Bin and then taking them out randomizes the tools needed to improve them.
Having a [[tool belt]] (at least 50QL) and [[key bindings|keybinding]] Improve and using the imp column can be very useful!