One of my players runs a Dungeon Fantasy Scout. But he's also not really conversant in GURPS. This generally isn't a problem, but for a scout this can be an issue. Your options are much greater than just "shoot two arrows per round."
If you come from games which don't require you to make some specific tactical choices, it's a big step to go to a game that does. Think of going from a video game (opening a door means hitting the "Open/Pickup/Manipulate" button on your controller) to D&D (opening a door means describing what you'll do to open it.) Same with GURPS - you need a bit more description and knowledge of what choices matter.
I wrote this with players new to GURPS, or new to bow-armed characters, in mind. It's most page references, because you should not only know the numbers and options but where they come from. Go look it up now, so you don't have to look it up at the table.
Know Your Arrows
This could be "know your bows" but generally Scouts will want a longbow or a composite bow to start with, and then stick with that forever. Just keep an eye out for better ones - especially Elven (better draw strength) and Balanced (better accuracy) ones. Arrows, though, are a constant choice.
The basic options are normal arrows ("broadheads") or armor-piercers ("bodkins"), per B277. Normal arrows do impaling, per the damage line on the weapon charts. Armor-piercers do piercing damage and add a (2) armor divisor. So if you normally do 1d+3 impaling, you'd do 1d+3(2) piercing (sometimes written as "pi") instead.
Impaling is useful against the Torso, Face, and especially vital locations (the Vitals, Neck, and Skull). It's less effective against limbs and extremities and unliving and homogenous targets (p. B380).
Piercing is less effective against non-vital targets and much less effective against unliving and homogenous targets (p. B380). Against vital target areas (Vitals and Skull, especially), it's just as effective as impaling or any other damage type. This makes armor-piercing arrows a great choice against an armored Skull (-7) or Vitals (-3) - assuming you can punch through the armor even with a (2) divisor. Skull is very easy to armor heavily, and Vitals is behind the torso armor. (Special Note: Beware legacy rules knowledge! This is not how armor-piercing arrows worked in GURPS 3e, and especially not how they worked in 1e and 2e. It's not "halves DR and halves damage" or "-2 to DR and -1 to damage.")
If your game is using alternate arrow types besides just normal and bodkin, Low-Tech p. 73 and Martial Arts p. 232 have lists of alternate arrow heads. The names vary slightly (Martial Arts has Willow Leaf, Low-Tech genericises this to Cutting) but the rules are compatible. (Low-Tech p. 78 also introduces arrow guides for darts and multiple arrow fasteners, but generally, they're reducing your accuracy and damage and serve to undercut your most needed traits for an archer - accuracy and damage! They are potentially useful against lightly-armored folks or high-Dodge targets if you can hit with many arrows, but otherwise, they're marginal.)
Cutting arrows are useful for limbs and extremities (assuming you can do enough damage to cripple them), the Neck (-5 to hit, x2 injury multiplier), or the Skull (-7 to hit, x4 injury multiplier). They're the best choice for general torso hits against unliving or homogenous targets!
Blunt arrows are useful for shooting crush-vulnerable targets such as skeletons, but otherwise tend to be fairly weak. Against a target with normal vulnerabilities, your best targets are Skull (-7 to hit, x4 injury multiplier), Neck (-5 to hit, x1.5 injury multiplier), and if you're using the rules from Martial Arts p. 137 Vitals (-3 to hit) can cause knockdown and stunning with any shock inflicted.
Most of the other specialized types are too specialized for much broad use - flaming arrows (p. B410) and fire-cage arrows might set fires in a pinch but don't do so much damage they're a must-have. Flight arrows have more range but generally ultra-long-range shooting isn't coming up in DF. Barbed arrows are only useful against foes you expect to have run off with arrows in them and need to pull them out.
Fine arrows are a potentially useful purchase, too, since fine cutting or impaling arrows will gain +1 damage. Cost makes it hard to get them in a Cornucopia Quiver, however!
Know Your Options
Is your GM using Tricky Shooting (Martial Arts, p. 121)? If so, know them well. Prediction Shooting is the best way to deal with Dodge-happy foes. Block is best reduced with Ranged Feints.
Quick-Shooting Bows (Martial Arts, p. 119) is built in to Heroic Archer, and it is detailed in Dungeon Fantasy 1: Adventurers (p. 14).
Power-Ups allow quicker shooting, double shooting, and other tricks. Out of the gate, though, stick to firing every turn!
Most maneuvers aren't going to help, but a few have special merit:
All-Out Attack (Determined) is worth a +1 to skill, and it is great for unopposed sniping or shooting into melee from a protected spot. Move and Attack takes away your Acc bonus (see below), but you can fire on the full run - great for running away after some actual scouting or charging into closer range. And Aim is handy for distant shots or making especially tricky shots into combat.
Know Your Targets
Out of the gate, a Scout has Bow-18 and Heroic Archer. If you shoot without moving, you get to add your Acc to every shot, aimed or not. If you took a longbow or composite bow (and if not, why not?), Acc is 3. You have a base 21 skill before penalties.
Although ranged attacks come with their own special issues thanks to the Size and Speed/Range Table, 21 is still very high.
Vitals (-3) is a great basic choice for shooting. The improved injury multiplier for both impaling and piercing means your normal arrows do a lot of damage here. A miss by 1 hits the torso, so even a near-miss is still a hit of some kind. Impaling, piercing, and crushing (with reduced effects) only. (Note: Skill 18 before range, counting Acc!)
Eye (-9, -10 if through armor) can blind a foe and has a x4 injury multiplier for all damage as it leads straight into the skull. Supernatural targets are rarely vulnerable to this, though - many have No Brain, No Eyes, or Homogenous. It might still be useful for blinding a target, but don't pin your life on it. Impaling and piercing only. (Note: Skill 12 or 11 before range, counting Acc!)
Face (-5) is often poorly armored compared to the torso or skull - not as many forms of armor cover the face very effectively. If a foe has light facial armor, this is a good target to consider shooting. Damage is normal, but major wounds here are more likely to cause Knockdown and Stunning (p. 420). (Note: Skill 16 before range, counting Acc!)
Chinks in Armor (-8/-10) are useful if you can suck up a -10 to halve DR (round up!) on the target location. It's only -8 on the torso. This can stack with other armor divisors, making it a way to get through very heavy armor coupled with an armor-piercing arrow. Not all armor (and not all creatures) have Chinks in Armor. Physiology or Hidden Lore might help here - ask the GM. (Note: Skill 13 or 11 before range, counting Acc!)
That's another point - game-mechanically you might know Vitals is x3 injury, but that doesn't mean your character knows where a triger's heart is from your shooting angle, or where a siege beast's heart is at all, or where the Chinks in Armor on a dragon's belly are. Knowing it might game-mechanically exist isn't the same as meaning you can target it. A mean GM (like me) will let you take a guess as a player ("I shoot it in the center of the chest!") and take the penalty ("Okay, it's -3 to hit.") and then resolve it. You might be right . . . or might just be shooting for the siege beast's triple-thick chestbone a dozen inches away from its organs.
Against armored foes, a hit against a heavily armored target is often about as useful as a miss. Better to aim for sometimes vulnerable but hard to hit (Eyes, Chinks in Armor, Face) or which maximizes damage and minimizes armor (Skull or Vitals, with a bodkin). Against a high-Dodge target, hitting or missing might not matter unless you've stacked enough enough Prediction Shot on it that you're at or close to minimum skill (10 for Deceptive Attack) because any normal hit will just be Dodged. And so on.
Finally, there are a lot of other ways to expand your effectiveness. Magical buffing, poison on arrows (against poison-vulnerable targets, that is), better bows, magical arrows, Power-Ups, Weapon Master, better vision in bad visibility, etc. But right out of the gate, a Scout is a very effective ranged combatant. The basics above can help you be so even if GURPS in general or bows in specific are new to you.