HP and MP Changing Points
This is one of the most useful strategy and you can use it for all classes, I kind of have already told you about this inside other topics indirectly, but it consists on using weapon's special abilities and specific clothing sets to start with a higher maximum HP or MP and gradually change to other equipments as your HP/MP goes down.
Most times you have to choose if you want to start with a higher HP or a higher MP, unfortunately there's no way to increase both status at the same time except by using a Tallum Blade*Dark Legion Blade +4 enchanted (S grade dual swords), it is the only weapon with a special ability that increases CP, HP and MP at the same time, but it doesn't give the maximum HP or MP that you can obtain at the start.
Talking about weapons first, to start with the maximum HP possible, you must use a weapon with the Health Special Ability, which increases 30% of your HP, while to get the maximum MP possible, you must use a weapon with the Conversion Special Ability, which increases 60% of your MP, but using a Conversion weapon is not always a good idea, because it reduces your maximum HP by 40%, so we get a second option which is the Mana Up Special Ability that increases 30% of your MP and doesn't have a HP penalty. Watch the following video with the Mystic Muse class as to get a example:
There I start with a Cabrio's Hand Conversion and Majestic Robe Set (the maximum MP possible at the start), and according to my mp decrease, I switch to the Dark Crystal Robe Set for the maximum casting speed after I lose the MP from the Majestic Robe Set. When the MP bonus from the Conversion weapon ends I change to the Arcana Mace Acumen for even more casting speed and damage.
In this case I could have changed to a Arcana Mace Mana Up before Acumen, but I made the mistake of clicking at the wrong weapon. As you can see, on each equipment change, my maximum MP gets lower, and the moment of these changes we can call MP and HP changing points, and the most precise you make these equipment changes, better it is, because taking the video above as example, with the Conversion weapon my damage is lower than with the Arcana Mace, so if I change it perfectly at the time the Conversion MP ends, I will benefit more from it's MP bonus without losing too much magical damage.
In this case, changing the weapons at the right time is also important because reducing my MP would also reduce the Mana Burn damage from the other guy, because the damage of this skill is based on the opponent's M. Def. and their maximum MP, so if the opponent's maximum MP gets lower, it will also burn less MP. Let's see another example, switching only clothing sets now:
In the video, I start with the Major Arcana Robe Set for extra MP and +7 speed, to get close of him faster. When the MP boost from the Major Arcana Robe Set finishes, I switch my clothes to the Light Titanium Set (custom set that is not available on every interlude server), which had the MP point at 2464 on the duelist, and I made the change with 2408 MP, almost exactly on the MP point.
You must be careful to do this with clothing sets, you must create clothing sets macros and always let the chest part to be the last piece equipped, especially if it's a robe clothing set, otherwise you might lose MP because the macro order is wrong. For clothing sets with the pants separated from the chest part, you need to put the chest part before the pants, being the pants the last piece to be equipped by the macro.
This strategy with robe clothing sets is mostly used by fighters, because they don't have weapons with good physical attack that can receive the Mana Up Special Ability, and light sets have a lesser MP boost than robe sets, while heavy sets doesn't give any additional MP at all. So for fighter classes that need to make their main damage with physical skills like Duelists, Grand Khavataris and Daggers this strategy is fundamental and gives a big advantage, if they use it the right way.
Discovering MP Points
To find the MP points with determinated weapon and clothing set you can just equip them outside the olympiad without a clan, completely heal your HP or MP, make the changes and keep the maximum MP points fixed on your mind, it's very important that you engrave them on your mind so you don't lose the changing time.
Let's take for example a Arcana Lord that is going to play against a Eva's Saint, he will need to start with maximum MP possible, which is usually 5109 MP with Majestic Robe Set + Conversion weapon, then he gets his MP slowly burned by the Eva's Saint with the Mana Burn, and when his MP goes down he must change to the Tallum Robe Set that gives more M. Def. than Majestic.
Here's a tricky thing, because unlike most robe clothing sets, the chest of Tallum Robe Set is divided on upper and lower body, just like the MP it gives. So for this change we need to put the chest before the pants at the macro, and to get the right MP changing point, you must look at it with the set equipped without the pants, which is 4506 MP.
After this, the next changing point is for the Mana Up weapon with 4059 MP, then for the Acumen weapon with 3355 MP. Don't forget about doing this test with jewels, the right dyes and without a clan, because there are clan skills that increases the maximum HP and MP, but they don't work at the olympiad, and you must consider all the variables that may increase or decrease your maximum MP.
MP variables: MEN points, jewels, clothing sets (MP bonuses and MEN points), Conversion and Mana UP weapons, S grade dual swords +4 enchanted, augmented weapons with MP bonuses or Item Skill: Bless The Soul, Bless The Soul from Hierophants, Soul of Sagittarius and Magnus Chant.
Discovering HP Points
To find the HP changing points the process is very similar, the difference is that your symbols are a very important factor. First you must get the Bless The Body from the Staff of Evil Spirits, just like inside of the olympiad, it has to be from the weapon because it's level 5, and then you choose the equipment that you will use. Let's take a Phoenix Knight with -8 Con symbols and without a Necklace of Valakas (it gives +445 of maximum HP) as example.
For a Phoenix Knight, the maximum HP possible is usually with a Health Forgotten Blade and the Imperial Crusader Set, which also gives +445 of maximum HP, so he would start with 6742 HP and since there is no other weapon that gives HP bonus to change after the Health HP goes away, he would go to a Focus Forgotten Blade when his HP reaches 5482.
For you to understand the importance of the symbols, removing all of them and making a +4 CON symbol, it's maximum HP goes up to 9433, so always choose them carefully. Clothing sets are also a big factor, some of them increase CON points and some decrease it, but usually it's not worth making changes between them for more HP because they decrease a lot of STR/DEX points.
HP variables: CON points, Necklace of Valakas, clothing sets (HP bonuses and CON points), Health weapons, S grade dual swords +4 enchanted, augmented weapons with HP bonuses or the Item Skills: Bless the Body/Battle Roar, Bless The Body from the Staff of Evil Spirits or Crystal Staff, Bless The Body from Hierophants, Battle Roar from Titans, Dreadnoughts and Duelists, Song of Vitality, Prophecy of Fire, Chant of Victory and Victory of Pa'agrio.
Equipments
To be able to use this strategy, you must know and understand about the weapons and clothing sets bonuses, so you can have a look at almost all of them on the links bellow, since if I would do a list for all the possible combinations for the 31 classes, it would be a endless list.
Remember that you don't have to learn and memorize everything in five minutes, just take a look and have your time to make tests and create your own strategies with this knowledge.
How To Use This?
On every match you should use this strategy, but you must learn how to identify against what classes you will need to start with a HP boost, a MP boost or even a little bit of both. Of course that in the beginning it will be a little hard for you, but you will get used to it.
You must think a little bit ahead at the preparation and choose your equipments according to the class of your opponent, for example if you are a Hierophant and you are going to play against a duelist, is it a good idea to start with a Conversion weapon? Obviously not, because duelists make a huge damage, and if you start with a low HP the chances of him killing you before you get the chance to burn his MP are way higher.