Unlocking hidden skills guide

You can unlock hidden skill in different ways. If you like mindforce chips you will start unlocks with Power Catalyst, if you start with mining your first unlock will be Ground Assessment or Extraction. Do what is most fun for you, but there are paths that will unlock the skills cheaper than others.
You can start with crafting or beauty or mindforce, but it is harder to skill there. It is better to go for something easier to skill and gain some additional skills in those professions for free before you move to them. There is no problem to start with mining, but it is always good if you have some fighting skills so you can get out if you are stuck or clear some creatures guarding your claims.

One of the first skills you will unlock even if you don't want is Animal Taming at Level 01 in Animal Tamer or Pet Handler profession. So don't think too much about that.

Best way to start is with some long range gun like Sollomate Opalo on Planet Calypso or any other laser or BLP rifle on the other planets from the trade terminal. Aim for unlocking the ranged combat hidden skill Marksmanship at Level 10 in any ranged (Hit OR Dmg) profession. Once you unlock that, you can be proud of yourself - you have done a lot in this universe. You can switch to different skills now, but it is good if you get the next unlock in ranged combat - Ranged Damage Assessment at Level 18 in any ranged (Dmg) profession. At that point you will be able to hunt most popular creature that give globals or some nice items. You are not even close to uber, but your choice of mobs to kill will be big enough.
Next unlock here is Serendipity at Level 30 in any profession it contributes to. This is the first hidden skill that increase your health every 1600 points.
With all that shooting even if you don't try you will unlock Spacecraft Systems at Level 05 in Gunner (Hit) or Level 40 in any (Hit) profession.
Next unlock in this category is too far away, so don't think about it for now.

Now it is good time to try Mindforce or mining. There are some good healing chips and some long range attack chips that can help you survive longer in Entropia Universe. And using mindforce chips is always fun. So start using some low level L (limited) chips to gain some skills and unlock the first mindforce hidden skill - Power Catalyst at Level 15 Any Mindforce (Hit or Dmg)/Biotropian/Reviver/Telepath. Big mindforce chips are hard to find and expensive so don't go for the next unlocks in this category.

At this point I will switch to Mining and get few unlocks there, but not everyone likes mining. If you don't like walking alone in empty spaces skip this paragraph. But if you want to be able to play without depositing start mining and collect knowledge how to be profitable. Mining also will help your crafting in the future. The first hidden skills you will unlock in mining are Ground Assessment at Level 12 Prospector and Surveyor Extraction at Level 15 Miner or Driller. They will unlock almost at the same time. And when MindArk implement treasure hunting you will be able to unlock Archaeological Lore at Level 15 Treasure Hunter.

Defense unlocks will come when creatures hit you a lot. If you want to skill there, collect sweat all day to unlock the first defense hidden skill - Avoidance at Level 25 Evader or Dodger. This will take long time so better don't think too much about it too.

/more soon/

HP (hit/health points) increase
One of the most important attribute of your avatar is the health or HP. If you have a lot of HP you will die harder and you will need less healing and this will result in less losses during hunt. The easiest way to increase your HP is by using melee weapons. Also you will notice that some of the hidden skills give you additional health point every 200, 400, 800 or 1600 points. Those skills are Serendipity, Coolness, Combat Sense and Commando. Unlocking them may be smart idea, but not easy to do.

You can find info about the hidden skills in different places, but down below I tried to separate them by category and arrange them in the order they are unlocked in that category. Sometimes it is possible the order to be different. For example level 18 DMG may come after level 20 HIT or in mining if you search only for one kind of resource, this skill will rise faster than the other. Anyway I think this will be useful. It is useful to me.

Combat - Ranged
Marksmanship - Level 10 in any ranged (Hit OR Dmg) profession
Ranged Damage Assessment - Level 18 in any ranged (Dmg) profession

Combat - Melee
Martial Arts - Level 20 in any melee (Hit) profession
Melee Damage Assessment - Level 18 in any melee (Dmg) profession

Combat - Any
Spacecraft Systems - Level 05 in Gunner (Hit) or Level 40 in any (Hit) profession
Serendipity - Level 30 in any profession it contributes to (HP increase every 1600 points)
Coolness - Level 40 in any (Hit) profession (HP increase every 400 points)
Wounding - Level 45 in any (Dmg) profession
Combat Sense - Level 50 in any (Hit) profession (HP increase every 800 points)
Commando - Level 70 in any (Hit) profession (HP increase every 200 points)
Kill Strike - Level 80 in any (Dmg) profession
Deep Space Knowledge - Level 45 Gunner (Dmg)

Beauty
Beauty Sense - Level 20 in any Beauty profession
Quality Sense - Level 35 in any Beauty Profession, Material Designer, Tailor

Construction
Material Extraction Methodology - Level 05 Material Manufacturer
Blueprint Comprehension - Level 10 in any engineering profession
Enhancer Technology - Level 20 Tier Upgrader or Enhancer Manufacturer
Equipment Methodology - Level 40 in any equipment engineering profession
Manufacture Methodology - Level 40 in any (non-equipment) engineering profession
Industrialist - Level 60 in any engineering profession

Defence
Avoidance - Level 25 Evader or Dodger
Quickness  - Level 55 Evader
Intuition - Level 80 Evader

Medical
Medicine - Level 20 Paramedic
Treatment - Level 25 Paramedic
Medical Therapy - Level 50 Paramedic
Doctor - Level 75 Paramedic

Mindforce
Power Catalyst - Level 15 Any Mindforce (Hit or Dmg)/Biotropian/Reviver/Telepath
Ethereal Soul Language - First successful Resurrection (Level 14 Biotropic)
Mindforce Harmony - Level 51 Any Mindforce (Hit) or (Dmg)
Force Merge -  Level 65 Electro Kinetic (Hit) or (Dmg)

Mining
Ground Assessment - Level 12 Prospector or Surveyor
Extraction - Level 15 Miner or Driller
Archaeological Lore - Level 15 Treasure Hunter
Mineral Sense - Level 30 Prospector or Surveyor
Miner - Level 50 in any mining profession
Drilling Expertise - Level 60 Miner

Tailoring
Material Comprehension - Level 05 Material Designer
Fashion Design - Level 15 Colorer or Tailor
Surface Composition - Level 20 Material Designer/Manufacturer
Coloring Methodology - Level 35 Colorer
Glamor - Level 70 Colorer

Science
Animal Taming - Level 01 in Animal Tamer or Pet Handler profession
Xenobiology - Level 30 Animal or Mutant investigator
Robotology - Level 30 Robot investigator
Scientist - Level 60 Investigator