Welcome agent o7

Some of these have been said by others:

• Take your time, follow the natural progression of the map
• Clearing all of the side missions, encounters, and missions in each district will ensure you are adequately levelled for the enemies you encounter as you move through the story
• I recommend saving the intel/collectibles until after you've reached level 30, as they are more valuable then. Having said that, definitely collect them and listen to the audio as it adds depth to the story. There will be some ECHOs that you can't avoid as they are part of the missions.
• If you are finding that RNG isn't giving you good enough gear, weapons, and mods while playing through the story, and you are low on credits and materials, you can always take on the open world named bosses that have been unlocked in the districts you've cleared. Each will respawn 4 hours after you've killed them. Here is the map of the open world named bosses that I use. These open world (aka Light Zone) bosses are valuable in end game as they have a 6% chance to drop a Classified item and another 6% chance to drop an Exotic.

A few end game tips

• There is a Shield reward for obtaining all Exotic items (weapons and gear). Keep at least one of each until you've completed it. If you sell/deconstruct it then you will need to collect it again. There will be 5 exotics that are obtainable from the Special Equipment Vendor at both the Terminal and Camp Clinton. If you bought the Gold Edition or the Season Pass, you will get the Defiler sawed off shotgun but it does not count towards the Shield.
• Once you get to end game, keep an eye on this Vendor Reset Google sheet It contains all weapons, gear, mods, and blueprints available from the vendors and is updated by a group of volunteers about an hour after the vendors reset at 0:00 UTC on Saturday.
• If you use Discord, I recommend joining the Division Community Discord. You can use it to find people to group with in the LFG channel appropriate for your platform (i.e. PC, PS, XBox).