In the new Travian you have Heroes and they get skill points when they level up, 4 to be exact. These can be spent on different attributes, which I will explain.

Now first off, the Hero that everyone starts with has a bonus depending on which tribe you are. That is explained below:

• Roman tribe: The hero skill “strength” increases by 100 points instead of 80 points for each skill point added.
• Gaul tribe:+5 Speed if mounted
• Teuton tribe:20 % “Cranny dip” (also known as “Plunder bonus”) for all units attacking with the hero.

First off, to make it a bit more simple I will write the following attributes and explain them quick, before looking at the tribe bonus.

• Fighting strength:
  Points  put into this ability increase the attack and defence value of the hero. Please note that your hero count as cavalry in case he is equipped with a horse and as infantry in case he is not equipped with a horse.
• Off bonus:
  Points put into this ability increase the attack value of the whole army by 0.2% per point (maximum of 20%). This bonus only applies if the hero is attacking with the army.
• Def bonus:
  Points put into this ability increase the defence value of the whole army (means all own troops deffending - the village there they come from is unimportant) by 0.2% per point (maximum of 20%) This bonus only applies if the hero is defending with the army. Other defending troops not under your control will remain unaffected by this bonus.
• Resources:
  Points put into this ability increase the resource output of the village where the Hero is located. You can opt to increase production of one resource only or to evenly spread the bonus across all resources. It still remains one skill. You can freely change that setting.

So those are the attributes.

Going onto the tribe bonus, the Romans will gain 100 points instead of only 80 points per skill point. This basically just increases the worth of your Hero, he will more or less kill a few more enemies. In addition however, he will also lose less health when sent out on adventures. For everyone who has gotten past the 10-20 day mark on a speed server recently, knows that the Hero will eventually start taking 30-50% damage each adventure (even normal difficulty). This means that you will usually only be able to check out one adventure a day, but increasing this skill will allow you to do more.

So, Gauls. Their Hero bonus is quite simple. If you have a mount, that means a horse, you will be +5 speed faster. This isn't major, but it is one of those little bits that help.

Onto Teutons, we see probably the strongest and most valuable bonus. This passive is one of the reasons why Teutons will be the Top Plunderers.
When trying to stop being a farm, people will build Crannys. A Cranny can hold 200 of each resource at level one and 2000 at level 10 (3000 for Gauls). The reason why these are great to build, is because these resources will be hidden and cannot be plundered, EXCEPT when you're a Teuton and have your Hero in the Plundering attack. It works like this:
If they hide 1000 wood, then the Teuton Hero with his race bonus, will allow you to plunder another 200 wood (20%) of what is in the Cranny(s). This works if the enemy has multiple Crannys as well.
In all fairness, it might be a bit too strong, because it allows you to plunder up to 20% of hidden resources in Crannys.

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Now, onto skill points.

If you're fresh out onto the server I recommend you to put every point into “Resource gain”. It will be very worth it, however it depends on your aggression. If you want to be topping the Top 10 Attacker/Plunderer I would go with “Offensive Bonus” (Off Bonus). This increases the attack damage of your troops, but it is only really worth it if you're going to raid MANY Oasis' and constantly, you need to beat the resources you could've gained by waiting.

My personal favorite is to train clubswingers (Teutons) or legionnaires (Romans) and put skill points into “Offensive Bonus”. I then proceed to farm out 5-6 Oasis'. I also allow around an hour to pass so that a few Nature troops will spawn, so that I will also be on the Top 10 attackers.

For Gauls I recommend going straight for resources. The Phalanx is weak and sending them to raid an Oasis would be not much but a waste of resources. If you then put points into “Offensive Bonus”, the outcome will most likely be you losing resources.

I do however recommend you to start putting all the skill points into resources early if you're not going to slaughter an Oasis or five. The only thing to note is that putting points into “Offensive Bonus “is very smart when you're getting 100-200 clubswingers or axemen / imperians. This will empower your troops and have major impact when you've gotten a few points into it.

This is how I recommend you doing it:

Are you very aggressive and are you looking to be on the Top 10 attackers/plunderers list due to farming 5+ Oasis'?
If the answer is yes, put every point into “Offensive Bonus”. Attack your first Oasis with about 10-15 clubswingers or legionnaires with your Hero. Keep building only troops and put every skill point into “Offensive Bonus”. REMEMBER! Always send your Hero when you're attacking an Oasis with troops. It's free experience for the Hero and it is not worth putting every point into “Off Bonus” if he doesn't get anything from it.

Are you looking to farm one or two oasis'?
In this scenario it is up to you. You can build “Off Bonus”/”Resources” side by side, but this is more or less up to preference. I might suggest you go “Off Bonus” if you have a Book of Wisdom (this resets points you've spent so you can spend them again) and then quickly swap back to “Resources”. If you do not have a Book of Wisdom however, my best suggestion would be you go “Resources” and build that until you find/get a hold of a Book of Wisdom to transition into “Off Bonus”.

Are you looking to just be turtling the entire early game and not plundering anything? 
Go nothing but “Resource”s. There is no other way to go. “Off Bonus” will yield nothing in comparison to “Resource gain”, simple as that. You might want to transition when you're going to attack a village with your axemen / imperians  (Swordsmen for Gauls), but this is more or less up to you.
Let's say it like this. When your 20 days into the game, you want to look towards getting “Offensive Bonus”. You shouldn't need the “Resource gain” after this, but it is of course helpful.

Also, if you're a farm, I suggest you do the following:
Buy Gold and get into Gold Club. Go to your Rally Point and click the evasion box, check that off. Then go to your Hero and go full “Def Bonus”. When you have a significant defense army, uncheck the same box and the two armies will clash. The bonus defense from the skill points will have a significant impact.