On the way to 30 pick up everything and dismantle it for crafting materials for when you hit 30. Don't really worry about gear while leveling because it won't mean shyt once you hit 30. Just get what you need for your current level and keep it moving.
Smgs are better than assault rifles in most circumstances just find an extended mag with preferably weapon damage or crit chance as the other stat.
Health isn't really that important of a stat. Enemies tear through you fairly quickly regardless of your health. Damage mitigation from the armor stat only seems to have a noticeable effect against other players. Just try to get around 45-50k health and put the rest into your other 2 skills depending on what role you're trying to play for your group.
Purples drop like candy in the dark zone so don't worry about extracting blues or greens once you get there
That's about all I can think about off the top of my head for now.
Makes my screenshot look like shyt lol
Need tips man
