For new players, a FAQ is "How do I level up quickly?" The common answer is various grinds, but this JUST gives you XP/Levels. It doesn't unlock any locations (Except the ones you run straight for to grind) Wayshrines, new Skill Lines, Quest Drops, nor anything else. Just levels, and not enough Skill Points to spend on all the Passives. (These are important for building your character after the first 5 Actives, and Ultimate. Then your Back Bar when you get to Weapon Swap.)
Any Race, Any Aliance
This really helps, not just for your Race/Class combination, but also so that you can farm all 5 Islands of the Trainee for Skyshards. (A total of 6 Skill Points just for that.) You can pick Any Race, Any Class, and any Starting Point, however I have some suggestions to minmax for XP:
Each Race has specific Skill Lines they level faster, after Level 5. Orc has 2: Heavy Armor, which is helpful for every character, because Light, and Medium Armor don't have as much Armor, so you can wear 1 Piece on the Chest, and make your character that much more resistant to Damage. I also suggest a Light Sash, so you level Light Armor at the same time, just in case you want to respec for magicka later. (There's also an Undaunted passive, that gives you Health, Stamina, and Magicka for each Armor Type you're wearing, but that's a long way off.)
Crafting. The same Passive also gives you bonus XP for EVERY CRAFTING SKILL. All of them, so if you ever plan on doing any Crafting, Orc is the best way o start. Even if you just want a Crafter to make sets for your Other characters, you want an orc, because they learn All of them faster after level 5.
Also, Stamina is good, because you can work on 4 different Weapon Skills (Bow, 1H&Shield, Dual Wield, and 2Handed.) I put it all in Stamina, which lets you sprint longer, and you also get a bonus to your maximum Stamina when you reach level 5.
Again, Any Alliance, but here's why I generally start Daggerfall Covenant: Port Hunding is Right There. There's a Skyshard right behind the Clothing Station, even at high level when i have Streak, i can teleport from Station to Bank, to station, in a square without taking a step. The Port Hunding Marketplace is the best place to start, if you plan on Crafting, and I suggest making Armor/Weapons right away, so you can unlock those trees, and their Passives, right away. (That's why so many Skyshards, so you can get Actives, AND Passives out of the way, as you level up skill trees.)
The order isn't important, gather the crew, Sky Shards, set sail for Betnikh, and run right for the Wayshrine for Daggerfall. Here's why:
The Fighter's guild levels from killing Undead, Werewolves, and Daedra. There ain't none on Stros M'kai. So, you don't waste any possible XP in that skill line by waiting to Join until you get to Betnikh, where there's Zombies, and ghosts to grind. (Also Glenumbra is full of spots like this. Some of them are popular, but just sticking to the Wyrd Tree, Angof, and Fouchu questlines, which give you Skill Points, will level up Fighter's guild.)
So, go ahead, and talk to the Guildmaster, find Aelif, and Merric, talk to the profit, and don't skip any Bookshelves you run past through all this. When I get back to Daggerfall, I hit up the Mage's Guild for their Library, and low, you unlock a whole bunch of skill lines. (If you have Any race, Any Alliance, then you can Fast Travel to Auridon, and grab the Shard off the roof over the bank.)
This has 6 Skyshards, on 1 island, and a Temple full of Undead to beat up for Fighter's guild Points. Also, you don't have to do any Quests for Skyshards. (There's one on Bleakrock that you have to crossdress, and fetch stuff from around town to get in the Mine.) I grab the Skyshard from the tower (I has a storm in it) then Suicide jump for a teleport directly to the central Temple (Of the 2 Moons) Wayshrine. grab the shrine from there, then head East to the Temple on that corner. Due West is the bridge to town (Where there's a Bank, and Crafting Stations. Finally!) then grab the one behind the Embassy, the one around the corner from a Scenic Point (Next to a Cave Entrance) then finally Shattered Shoals. You can run this quest if you want to, it's XP, but the one in town with the Maomor Embassy is really dull, and fetch-questy. You don't really get any Skill Points from it, there's a Wayshrine right there, and you can grind Skeletons on the East corner of the Island.
Has 2 Temples (Alied sites) full of Spirits to farm for FGP. Also an Occupied graveyard, and the island Quest comes through with some halfway decent fights. I like fights, a lot better than fetching Mushrooms for Abnur Tharn, and I don't have a single build that doesn't benefit from Silver Leash. (Arguably a Magicka Dragonknight, but that's basically it.)
I DELETE a character, every day, and it takes me about 10 hours to get one to level 50 (Depending on the Build. Some are faster than others.) ^That right there will get you up to level 15, with a Bar Swap, and enough Skill Points to invest in 2 Weapon Skill Lines. Before Daughter of Giants.
Good Luck, Have fun.