So I am creating a new save.

Am actually wondering how does everyone here go about completing the guild quests and in what specific order? I understand that not everyone joins all the guilds but if you did what specific order did you follow.

I was thinking of starting out with the Dark Brotherhood, the companions and then the thieves, then focusing on the Dawnguard, before starting the Civil War and then the main quest.

Now I've been told that if complete certain guilds before the other, it could bug out future quests and NPC dialogues change accordingly. Any truth in this?

Whatever suits your character.
I rarely make characters that do all guilds.
My last character joined the TG then the DG then done the MQ and died.

Me personally I would pick the Dark Brotherhood 1st because the rewards are universally good at all levels but it depends on your character. If you are someone who is focused on Heavy Armor, you'll probably want to do the Companions 1st. Mages should probably do the College of Winterhold 1st. Usually I would save the Thieves Guild for last because it's the only guild out of the main 4 that have quest level scaled rewards.

If your a Stealth Build you absolutely need to do the Dark Brotherhood 1st. Archers should do both the Dark Brotherhood and Dawnguard's main quest (Siding with Dawnguard) in order to get Crossbows and the Dark Brotherhood gear that benefits archers and Stealth Builds.

Makes the most sense to do the Thieves Guild early, when you're young and broke, right?
In other words, the Harbinger of the Companions is not very likely to head to Riften and try his hand at some pickpocketing...

I try to do the TG first (right from Helgen).
Doesn't make sense any other way...

Usually takes until level ~40 to get the TG 100% restored!
There's easily 40 levels of only TG and miscellaneous stuff...
Then after restoring the TG I thought I would maybe go back to College @ 40.

This. I play mostly warriors so most of my characters join the Companions even though they're not handled well in game. I don't think I've ever played a character who's joined every guild as it doesn't make sense to me.

Speaking of Companions, I always have to hit the giant with an arrow before they kill it to earn Aelas respect

I'd rather hit Aela!

For stealth, my preference is to do the TG first & then the DB. And if i feel like it maybe the others.

ha I'm trying to earn the Companions respect not pay my final respects after killing them all.

btw sweet avatar pic

Depends on the character. I'd rather do whatever guild my character has in mind after I visited the majority of the cities.

Many of my character regularly join the Companions or the College.

Since I don't like the ending of the Dark Brotherhood, I just destroy them.

Thieves guild is just too long for me, not mentioning all it takes to lead them.

Mifune san and I thank you!