1. Learn the quests so you know what works vs each mob, and more importantly, what doesn't work.
2. Play an effective build. Go deep and narrow with a build to be the best you can with it, rather than a jack-of-all-trades. Newer content is much less forgiving when it comes to monster saves. So your DCs for abilities need to be a focus, not an afterthought. If you're melee, you need to be breaking DR.
3. Farm out the gear you need, ideally before you play it. DDO provides excellent gear with set bonuses that doesn't require raiding. You can solo if you chose, but that leads to the next tip. Cannith Crafted gear is ok for leveling, but it's not going to hold up in mid-high reaper skulls.
4. Bring a full group. The game is infinitely easier with more people in the group: Mobs die faster, which means there's a smaller window for them to do damage which in turns you're minimizing the chance that you're going to die. More people also means more hands in the chest to pull named items.
Past lives are not required for reaper XP. Hardcore proves that season after season, where folks run R4 Legendary quests with first life characters.
You don't need to run R10 to accumulate reaper points. I soloed my way to wings on one character just running R1 while leveling and R3 Legendary content each life -- because of #1, #2, and #3 above.