Everyone knows Takei's timeline is a complete mess. There is an official timeline in the first official character guide, but it makes absolutely no sense with the context of the manga itself, and both anime add a layer of confusion by cutting out most indications of the passage of time and making it feel like the beginning takes place in a very short period of time, even though it actually lasts longer than a year.

This is the timeline I personally use for the sake of my fanfiction. It is adapted from this timeline by Tumblr user mageofthepen, which is the most thorough and accurate timeline I've encountered, fully taking into account Takei's retcons and alterations and making expository notes where needed. I highly recommend it.

Naturally, I have altered and rearranged a few things, picking the events that fit the most cohesive timeline, even if it's still a bit of a disaster and definitely not my ideal timeline. Can't change that without changing the entire story unfortunately...

1998

January 28th

• First day of the Year of the Tiger

May 12th

• Yoh and Hao's 13th birthday

May 17th

• Lyserg's 12th birthday

Late May thru Mid-July

• Yoh meets Manta and starts his first year at Shinra Private Academy

July 20th

• Sea Day
• Start of summer break

July 22nd

• Anna's 13th birthday ⁽¹⁾

Late July

• Ren arrives to try and steal Amidamaru
• Anna arrives three days after Ren

August

• Anna's bootcamp hell
• Manta doesn't see Yoh at all during this time period

Late August

• Start of fall term

September 5th

• Manta's 13th birthday

October 2nd

• Chocolove's 13th birthday

Late October thru Early November

• Jun and Li Pailong's introduction

November 27th

• Horohoro's 13th birthday

Early/Mid-December

• Tokagerou arc ⁽²⁾

December 24th

• Ryu's 18th birthday

1999

January 1st

• Ren's 13th birthday

Early thru Mid-January

• Manta states it is a new year to Ryu following the events with Tokagerou and subsequently the comet appears that night
• Shaman Fight test with Silva

Early February

• Yoh vs Horohoro

February 16th

• First day of the Year of the Rabbit

Late March thru Early April

• Yoh vs Faust ⁽³⁾

May 12th

• Yoh and Hao's 14th birthday

May 17th

• Lyserg's 13th birthday

June

• Manta and Yoh discharged from the hospital
• Trip to Izumo
• Ryu starts training with Yohmei

July 22nd

• Anna's 14th birthday

September 5th

• Manta's 14th birthday

September

• Yoh vs Ren, immediately followed by the opening ceremony
• The next day - Horohoro invites Ren to Yoh's for a celebration
• Ren leaves the following morning
• Boz and the Ryu and Tokagerou team-up reveal ⁽⁴⁾
• China arc
• Ren takes one week to reach home after the prelims end
• Yoh and co. take an additional ten days to reach Ren's home for their rescue mission
• Ren vs En
• Ren's family (sans En) hosts a meal for Yoh and co.
• Ren and then Yoh and co. leave the day after defeating En

October 2nd

• Chocolove's 14th birthday

Early October

• Trip through America
• Day 1
• Drive through the night arrive in Yonta Fe at noon
• Lilirara
• Day 2
• Leave Yonta Fe
• Day 3
• Meet Lyserg ⁽⁵⁾
• Day 5
• Horohoro crashes on the way to Duringo and is knocked out
• Yoh and co. arrive at Duringo
• Start of Bluebell and Apollo mini-adventure
• Days 5 thru 7
• Horohoro is unconscious under Bluebell's care
• Day 8
• Horohoro sets out to find Apollo
• Day 9
• Horohoro rendezvous with Yoh and co. in Duringo
• Day 10
• Showdown at Mesa Verdede
• Anna and co. arrive in America
• Yoh and co. arrive at Patch Village
• Day 11
• Anna and co. arrive at Patch Village
• Hao and co. arrive at Patch Village
• Marco grooms Lyserg, and Lyserg joins the X-Laws
• Yoh and co. meet Chocolove
• Team the Ren forms
• Faust returns
• Team Funbari Onsen forms

Late October thru December

• The remaining two and a half months are spent training
• Lyserg is kept hidden away by the X-Laws and doesn't see anyone else
• Anna tells Yoh about being Hao's descendent and teaches Yoh, Ryu, and Faust the Shamanic Oracle (but not the twins part)
• Horohoro challenges Chocolove for the position of Ren's right-hand man

November 27th

• Horohoro's 14th birthday

December 24th

• Ryu's 19th birthday

2000

January 1st

• Ren's 14th birthday
• Deadline to reach Patch Village

Early January

• Fights move to Island of Tokyo
• Day 1 of Main Tournament - First Round
• Team the Ren vs Tsuchigumi
• Team Nile vs X-I
• Team Funbari Onsen vs Team Icemen
• Hao tries to recruit Ren
• Yoh visits Lyserg
• Day 2 of Main Tournament - First Round
• Hanagumi vs T-Production
• Hoshigumi vs X-III
• Stadium rebuilt ⁽⁶⁾
• The Asakuras ask the Taos for permission to train Ren in the Shamanic Oracle
• Twin reveal ⁽⁷⁾
• Kabbalahers vs Mariachi
• Jun, Tamao, and Anna vs Hanagumi
• Ren vs Mikihisa
• Ren vs Peyote, Hang Zang-Ching, and Turbine
• Ren dies
• Horohoro learns Shamanic Oracle from watching Ren vs Mikihisa
• Yoh drops out of the Shaman Fight in exchange for Jeanne reviving Ren
• Horohoro and Team Icemen vs Big Guy Bill and Blocken
• Ryu vs Peyote and Turbine, and Ryu is saved by Gandhara
• Golem mini-arc
• Chocolove dies and is revived, having given up his sight
• Day 3 of Main Tournament - First Round
• Haiti 800 vs Tathagata
• Cowboys vs Deva
• Opacho stays with Yoh and co. and insists Yoh must rejoin the Shaman Fight
• Yoh vs X-Laws in order to rejoin the Shaman Fight ⁽⁸⁾
• Day 4 of Main Tournament - Second Round
• Yoh reveals the Plants plan to the group
• Team the Ren vs The Wisdom Kings
• Hanagumi vs Magical Princess
• X-II attacks Hao and is annihilated
• Anahol vs X-I, Manta, and Tamao
• Lyserg, Jeanne, and Marco die, but Marco is immediately revived as Jeanne's last act
• Sati sends Yoh to Hell
• Tsukigumi attacks Sati and co. killing them
• Ren, Horohoro, and Chocolove are sent to Hell
• The whole world becomes aware of the Shaman Fight because of the X-Laws' laser
• Yoh is revived by Faust
• Ren, Horohoro, and Chocolove are revived by Jun
• Peyote's betrayal at the beach as the Oyamada company waits off shore
• Yoh and Hao have coffee
• Sati, Jeanne, and the rest of Gandhara are revived
• Day 5 of Main Tournament - Second Round
• Team Funbari Onsen vs Team the Ren, which is interrupted by Lyserg's return from hell
• Tournament fights end
• Team Funbari Onsen, Team the Ren, X-I, and Hoshigumi all advance
• All Gandhara teams withdraw along with the Kabbalahers
• Yoh and co. enjoy the onsen after their wounds are healed, Hao joins
• Ren's crush on Yoh finally ends
• Next Day
• Hao's massacre and subsequent revival of his victims at the beach
• Departure for Mu
• Everyone drops out, Hao is declared Shaman King
• Luchist vs Marco
• Vs Namari - Ryu's death and resurrection
• Vs Bron - Ren and Horohoro die/resurrected, Jeanne left behind
• Ren vs Magna
• Hao reaches the King's Shrine
• Vs Radim - Faust's death
• Redseb and Seyrarm use Golem to attack Hao, they fail and die
• Yoh and co. spend the night at Kalim's plant
• Redseb brings SOF
• Final Day
• Horohoro vs Kalim
• Opacho vs Renim
• Ren vs Nichrom
• Vs Thalim
• Yoh vs Silva
• Vs Rutherford - Hao awakens
• Everyone vs Hao's heart

February 5th

• First day of the Year of the Dragon

footnotes

1. Anna has no canon birthday. This is the birthday given to the Kyouyama Anna in Takei's "Itako no Anna" and Butsu Zone

2. This mini-arc starts in the fall but is retconned into ending during winter in order to lead into the comet's arrival

3. Silva states it is spring break, which is around March 25 to April 5

4. Takei retconned Ryu into the Shaman Fight, as it is unrealistic for Ryu to train with Yohmei for three months, then pass his prelims and defeat two other Shamans during this time

5. Lyserg introduces himself as 14, but his birthday is in 1986 and he is 13 at this time

6. It is unclear how long it takes the Patch to clean and fix the stadium, but the scenes during this time treat it like it is a very short period of time

7. In Ch. 141, Yoh explicitly states it is early January

8. In Ch. 211, Marco states it has been six months since he met Yoh, but this is not possible during the story's timeframe