Runescape players who play the Clan Wars mini game know that most of the time the bigger clan wins because at the beginning of an average clan war there is a lot of confusion with both teams running around and people attacking randomly. This means that if the teams are about the same average level the team with more combined hit points will win.
Smaller Team Strategy
In this scenario the smaller team should retreat from the fence and regroup on one square far back towards the portal. The team should go to one of the back corners and stay away from the back center because normally the other teams' initial charge will be focused there. By going to one of the corners it will split up the larger teams' forces when they try and find the smaller team. Now that the larger teams' forces are split up the smaller team just has to wait for small groups or individuals of the larger team. When the group attacks the smaller team they won't be able to “pile” a single player as easily because the whole team is on one square. This also means the smaller team can coordinate a more efficient defense against the attacker (like the 300 Spartans). Hopefully by this time the larger team will be spread out enough that the small team can finish with one group before another one finds them.
Bigger Team Strategy
In this scenario the bigger teams' goal should be to split up the smaller team. By splitting up the smaller team the larger team can make use of its greater combined hit points. To split up the smaller team the big team should focus on the lowest levels of the other team. Most low levels are inexperienced and will flee. After seeing their clan break up the other members will start to scatter. The bigger teams' members should chase people of their own level so it will be an equal battle and the bigger teams total hit point advantage will ensure its victory.
Class Ratio
After playing Runescape clan wars for a couple of months I have found a good class ratio for a clan. The ratio that I found that works best for a clan is 1mage: 2rangers: 5warriors. I have found that this ratio allows a clan to hold off another clan's warrior while putting pressure on their mages and making their rangers ineffective. This ratio accomplishes this by having the warriors as a barrier, the rangers as a forward offensive against lightly armored mages and the mages are used to hit high numbers on the heavily armored warriors.
Recommend Spells, Weapons and Arrows
Mages
Bind (20), Fire bolt (35)
I found that these spells are the most useful and cost efficient. For a mage the most important thing to do is keep a good distance between itself and a warrior. By having a bind spell a mage can stop a warrior in its tracks, get to cover and continue to attack. The reason I recommend fire bolt is that it has a good hit for a relatively low cost. Some of you high level mages out there may ask why not use fire blast (59). My answer to this question is that although the highest you can hit with fire bolt is 12 compared to the fire blasts 16 it is 3 times as expensive as fire bolt and does only 1/3 more damage.
Warriors
Rune scimitar (40), Rune war hammer (40)
The two weapons that are most useful for a warrior are the rune scimitar and the rune war hammer. A warrior should carry both if possible. The rune scimitar is an all-around fast slash weapon with descent damage. It is extremely effective against mages and ranger due to their light armor. However, it is not very good against other warriors. This is where the rune war hammer will come in handy. Despite its slow speed and weight it packs a punch against the heavy plate armor worn by most warriors. Warning: The war hammer is extremely inefficient against mages and archers.
Archers
Steel arrows w/ maple short bow (30)
The most effective arrow and bow combination for a ranger during clan wars would have to be the steel and maple short bow combo. The reason this combo is really effective for non-member rangers is that it balances cost efficiency, power and speed.
Steel arrows: 12gp
Maple short bow: +29 ranged and twice and twice as fast as long bow.