The Ranger is all about ranged combat, keeping enemies at bay at a distance with a torrent of arrows. Due to being able to attack while keeping away, many players get the false belief that they can focus on all offense and just skip out the defense, relying on micromanagement to stay out of harm's way. Unfortunately, such players then realize their mistake as they get cornered and surrounded by high level monsters that take no time at all to tear them apart. Because of that, a build that balances both offense and defense is needed to play Path of Exile well.
A good answer comes courtesy of an elemental bow ranger build that takes most of its offense from elemental damage so that there can be enough points put into survivability. It's a cookie cutter build with a bit of Blood Magic to keep things interesting. This is definitely not the glass cannon build that most novices would lean towards, but a balanced configuration that puts just about everything into consideration. This is a Ranger build that is for the smart and discerning Path of Exile player who is aware of what is ahead and approaches every problem with a plan.
This build does well with decent Path of Exile items equipped, since most of the offense comes from the elemental damage you're dishing out. Either its Lightning Arrow or Ice Shot with Split Arrow, you will deal extra damage and have crowd control to boot. As for defense and survivability, you can get Iron Reflexes that turns Evasion into Armour, as well as Blood Magic/Life Leech for replenishing your health in the middle of a fight and Unwavering Stance to be immune from getting stunned. Those skills should get you started in understanding how this build works.
The good thing with these particular skills is that they are fit for most of what you'll encounter in the game. For instance, Unwavering Stance fits most of the maps that you'll crawl in since they're full of enemies that can swarm and overwhelm you. That also does well with Life Leech since there is a constant stream of enemies to suck life out of, so long as you don't get hurt too bad too quickly. While you can kite the enemies to ensure your survival, you won't have to do that as much with this build since you'd be hardier, so you can breathe more easily and focus on taking care of the enemies. Kiting a lot also means more time needed to take mobs of enemies out. Be wary though of ranged chaos dealers like Vipers, as well as Skeleton Archers or really quick charging mobs that can close the distance quickly like rare rhoas.
For most situations, the balancing act between DPS with the amount of health is up to your preferences and requirements. You have some active skill gem combinations to choose from, each for various situations. First off, Lightning Arrow or Ice Shot with Weapon Elemental Damage, Faster Attacks, Lesser Multiple Projectives, and Life Leech or Culling Strike is great for most of the game, letting you take out mobs relatively easily. There's also Split Arrow with Faster Attacks, Weapon Elemental Damage, Culling Strike, and Life Leech if you're up against really big mobs. Finally, Elemental Hit or Frenzy with Faster Attacks, Weapon Elemental Damage, Culling Strike, and Life Leech is perfect against bosses.