Human abilities are divided into three distinct schools offering different skills that are unlocked throughout the course of the game. Below, you can find a list of recommended abilities that are useful to unlock early on. Unlocking abilities takes neuromods that can be found while exploring the station. Every ability takes one to several such items. The places where you can find neuromods are listed in mission descriptions and in the chapter devoted to important game elements.
Recommended abilities to be unlocked at the beginning of the game
Hacking (Scientist tree) is an ability that you might use very often. It is so because most of the computer workstations, terminals, turrets, and other interactive devices require hacking if you don't have the password. The lowest level of Hacking can be unlocked with just one neuromod so you can starting hacking very early in the game. However, do try to quickly advance this ability to the second (4 neuromods) or the third (6 neuromods) level which will let you hack more complicated devices.
Leverage (Engineer tree) is a very helpful ability, especially in exploration, since many pathways are blocked by large objects that the protagonist initially can't even push. The ability also has offensive use because movable objects can be thrown at enemies to hurt them. The lowest level of Leverage can be unlocked with just one neuromod, but do try to unlock the highest level (4+6 neuromods) which will allow you to lift all interactive objects.
Repair (Engineer tree) is a very useful ability if you like to explore thoroughly. The game lets you repair broken objects (the pool increases with every unlocked level). However, remember that you need spare parts in addition to the ability. The first level costs one neuromod but the remaining ones are unfortunately more expensive (4 and 8 points respectively). It's also worth mentioning that apart from the main ability, you can also unlock lesser abilities connected to it - Dismantle, Gunsmith, and Suit Modification. Focus on Suit Modification first since it increases inventory space and the Suit Chipset limit.
More recommended abilities to unlock
Physician is an important ability while playing at higherer difficulty levels since it significantly increases the efficiency of first aid kits. If you chose normal difficulty, food should provide enough healing (or you can unlock the ability slightly later).
Firearms is an interesting choice for combat if you like to use classical weapons. You can count on dealing more damage and a higher chance of scoring critical hits.
Conditioning is an ability that takes just one neuromod for unlocking its basic level. Then, you can decide whether or not you want to develop your character in terms of stamina, endurance, or agility.
Combat Focus is an ability that you probably know from other action games. It lets you slow the time down to make shooting enemies easier. Additionally, the protagonist's movement uses 50% less Stamina in this mode. Attention - this ability is connected to the Dead Calm achievement.
Stealth may not be the key component of Prey but it does prove helpful in certain situations. The base level of this ability takes just two neuromods to unlock. You can later decide if you want to leave it at that or to further develop the protagonist's skill of avoiding detection. In the latter case, consider unlocking Sneak Attack which grants a huge damage bonus when surprise attacking.