Listen to Darjelo.
You need multiple sets of mods with +100 to +140 speed, and that's without counting the %speed bonus from a speed set. And these mods need to come in different flavours, from defense to offence to Pot/Ten.
If you run a speed primary on the arrow, that means you need to average +14 on the low end for the sets you're going to use in events. At the high end, and not using a speed primary arrow, that's +24 speed per mod. Just to set yourself up well, you're going to need 20-30x Offense mods that fit this profile, 10-20x Crit Dmg mods, 12-20 Potency, 12-20 Crit Chance and so on. You need this bc sometimes you'll be looking for, just as an example, potency with offense, but other times you want potency with offence AND crit chance (throw in high speed and this can be a hard mod to find). Still other times you might only care about potency, so you just grab a high Pot mod with as much speed as you can get, not caring at all about other stats. To be able to build the right set of 6 mods for a particular character for a particular event, you need many good mods in your inventory where speed is always decent to excellent and the other stats show up in a variety of combinations.
Younger accounts will struggle to average +18 and a few of their "good" mods might still be +10 speed, which paired with a +20 can still avg +15. But you can help yourself by learning which mods to buy and level and which to sell. You have limited inventory, so you have to be careful with it. And yet, to get those strong collections of each mod type, you're going to have to level thousands of mods. Most won't work out. Don't be afraid to sell bad mods; better ones are always around the next corner.
Apologies if you're familiar with this, but I've remedied literally hundreds of ppl and a surprising number didn't know some basic principles about modding (like don't buy or level a mod with mismatched set bonus & primary). But even if all this stuff is old hat to you, it doesn't hurt to have ppl reading along think about their own mods and what they consider good.
