Shadow Dragon isn't forgiving, and your first playthrough will show you that.
I keep meaning to write this properly because the questions I see asked about Fire Emblem Shadow Dragon Guide are always the same ones from people who haven't actually grinded through the first three maps yet. They need to know how weapon triangle works at a systemic level, where people waste their first two playthroughs trying to figure it out, and the one or two specific map strategies that aren't obvious unless someone has sat through at least five runs. Weapon triangle in this game is simpler than any later entry, which is both a relief and a problem. Lance beats sword, sword beats axe, axe beats lance. That's it. There are no multipliers beyond the base 50 percent bonus and the 25 percent penalty. What people don't realize is that positioning matters more than the triangle itself on most early maps. A wyvern rider will ignore your swordsman and go straight for the pegasus units because they're closer, regardless of the triangle advantage. You learn this on Chapter 2 when Marcan dies because you positioned him directly in the dragon's path. He was a lance user against a dragon. It didn't matter. Distance mattered.
Where to find a proper Fire Emblem Shadow Dragon Guide
The most complete version lives on a number of community wiki pages and old-school forum threads. Search for the full guide by Martel or the SNES central archives. Downloadable PDF versions circulate on various retro gaming forums, but honestly the wiki version is usually the most updated since people have patched the typos over the years. The original Japanese manual has different name variants for some characters, so if something feels off compare it to the English wiki entry. Stat growth is where this game separates careful players from frustrated ones. Each character has growth rates in HP, strength, magic, speed, luck, defense, and resistance. These percentages are fixed at recruitment and never change. Marthan starts with abysmal speed growth, which means he rarely gets double attacks until late in the game. You can't fix this. You work around it by keeping him behind frontline units and using his high defense to survive hits he can't outrun. Marth's growth in particular is deceptive. His strength grows nicely, but his speed starts low enough that early on he'll be getting hit before he hits back on several maps. I learned this the hard way during a run where I promoted him to lord too early and he got stuck behind a door in Chapter 3 while a single archer whittled him down. The workaround was simple: keep him at warrior rank until Chapter 4, let him reach at least level 7 or 8, then promote. By that point his speed had climbed enough to compete.
Lyn's promotion path in the remake is clean, but in the original SNES version she's locked to the Pegasus Knight class with no direct sword promotion until very late. This means early chapters you're running her as a flying unit who can't effectively counter lance enemies. The fix is to avoid any chapter that has a heavy lancer presence until you've promoted her through the standard path. That's Chapter 12 in the original, which aligns roughly with when you get access to the Swordmaster class through normal progression.
Get the Full Details
Map strategy principles that actually work
The village mechanic is the single most underappreciated system in this game. Every village on a map gives you items when you send a unit to it. Some give weapons, some give keys, some give repair items, and a few contain hidden treasure. The trick is that you need to send a unit who can reach the village without stepping into enemy movement range, because enemies move after your turn and will attack anyone in range. This means checking enemy movement tiles after every unit's turn on maps where villages are exposed. Turn order matters more than in later entries. Because this game doesn't have the turn-limit pressure of the newer titles, there's a tendency to take things slow. On maps with limited supplies or where enemies patrol specific corridors, moving too slowly means enemies rotate into positions that block your advance. I once wasted an entire run on Chapter 6 by being too cautious with Tine. She could have cleared the passage in two turns if I'd pushed her forward aggressively instead of waiting for the archers to cycle away. The boss fights have predictable patterns. Hardon in Chapter 4 always targets your weakest unit first, which is useful information if you're short on healing items. Put your tankiest character near him and let the healers work from behind. Duane in Chapter 9 is slower than he appears on paper because his movement is limited by the narrow corridors. Use that to your advantage by funneling him into a choke point where only one of his men can engage you at a time.
Items and economy
Weapons break in this game. Not often, but they do, and when a cheap iron sword breaks in the middle of Chapter 7 you're left with a unit who has no weapon at all. The solution is to hoard repair stones from every village you can reach and never spend them on units who are close to death. A repair stone costs about two gold pieces worth of village income, and replacing a broken weapon costs anywhere from ten to thirty depending on the tier. It's almost always cheaper to repair. Gold management is stricter than later games. Merchants appear on select maps and their inventory rotates, but they never restock within a playthrough. If you see a merchant selling a silver sword on Chapter 5, buy it. You won't see another silver sword seller until Chapter 14 at the earliest, and even then the selection is limited. I've lost track of how many runs I've started with a broken weapon in my main fighter because I refused to spend fifty gold on a replacement at the Chapter 3 merchant.
Common mistakes that derail runs
The biggest mistake is promoting units too early. The stat bonuses from promotion are significant, but you lose the ability to gain experience at lower ranks where the EXP curve is more forgiving. A level 9 knight who gets promoted loses the chance to reach level 10 as a knight and gain those extra stat points. The rule of thumb is to keep units below level 10 before promoting whenever possible.exceptions exist for units who clearly won't see much use, like support characters you're only keeping alive to open a door. Another mistake is ignoring the difficulty settings. The game has Normal and Hard modes, and Hard mode changes enemy promotions, stat multipliers, and occasionally adds enemies to maps. If you're reading a Fire Emblem Shadow Dragon Guide for the first time, start on Normal. Hard mode is fine for a second playthrough when you know the map layouts cold. Marth's sword is unbreakable and should never be sold or stored. I once traded it at a merchant for three hundred gold thinking I could buy a better weapon. I couldn't. No weapon in the game surpasses Marth's sword in the early to mid game, and you lose access to it permanently once sold. That's a run gone.

What the guide won't tell you
There's a soft cap on stat growth around 20 or 21 in base stats. Once a character hits that threshold, growth becomes unreliable regardless of equipment or promotion status. This means pushing every unit past level 15 is wasteful unless they still have solid growth rates remaining. Focus your experience distribution on units who are under the soft cap and have good growth percentages in the stats you need. This is how you build a team that's actually viable by Chapter 15 without wasting resources on units who've already hit their ceiling. The game has no New Game Plus in the traditional sense. Starting a new file means starting from scratch with no carried over items or experience. The only thing that carries between runs is your knowledge of the maps, which isn't particularly helpful on your first attempt. This is why the guide approach of studying map layouts beforehand pays off. Memorizing where enemies spawn and what they carry saves hours of failed attempts.