So, if we take away the amount of dots on a mod, the colour of the mod (which are quite basic) and the level of the mod , there are 3 pieces of information.
Mod set - This is the icon of the mod. You need 4 (speed, Crit Damage and offence) mods to complete a set. You need 2 mods of any other type to complete a set. When you complete a set, you get a bonus. For example, a completed (4 mods) speed set gives you an extra 10% speed.
Primary - Each mod has a primary 'buff'. This is the word in bold to the right of the mod. Different mod shapes have different primaries. For example, the arrow is the only one that can have a 'speed' primary. The mods on the left side are very restrictive on which primaries they can take. The mods on the right have a lot more choice. This means that, the mods on the right, with the correct primary are more valuable to you.
Secondary - Each mod has 4 secondary 'buffs'. Now, the speed is boldened. As this tends to be a very important factor for most characters. Rule of thumb; the more speed, the more happy happy. Some characters will work considerably better with other stat buffs. For example, Dr Aphra works so much better with high potency. So, you'll be looking for mods that have potency and speed for her. Preferably on the primaries, but if you can't do that, on the secondaries.
I have no idea what character needs what mods! No problem, we have swgoh.gg, the swgoh guide to the galaxy. Simply google "swgoh.gg best mods for .....Lobot" and you'll get all the information you need. OK, this isn't tailored specifically for your Lobot, but it's what the majority of high end players are doing.
Let's try it:
"Hey swgoh.gg, what are the best mods for Lobot?"
Mod set - health (x2) Speed (x4)
OK, if we look at the mod set above. We see that we will get 2 bonuses (4 speed mods = 1 bonus) (2 health mods = 1 bonus). So, we're going to get a speed and health bonus.
Primaries
Arrow - speed (obviously, if were taking a speed mod set)
Triangle - Protection
Cross - Potency
Circle - protection
(Diamonds and Squares only have 1 primary stat, so aren't listed)
So, from this information we can see that Speed is very important. Make sure all your mods have speed on a secondary. Other than your arrow which has it on a primary. (If a mod has something on a primary, it can't be on a secondary too).
Potency looks sort of important. If you can get potency on your secondaries, it'll help a bit.
Keeping him alive also looks important. (health set, and protection primaries). It looks like protection is more important than health. (We chose a protection primary over a health primary on the circle). So.......protection and health secondaries look good, protection a bit better. It doesn't look like he does any damage so Crit dmg, crit chance, offence look sort of worthless.
Extra information if your head can take it
Although earlier I wrote 'if a mod has something on a primary, it can't be on a secondary too', this isn't quite the case. Some buffs have a direct figure buff and a percentage buff too. For example 'health. So, you could have 2 secondaries or 1 primary and 1 secondary health buff, one being a + figure, the other being a + percentage.
Percentage buffs are significantly better than direct number buffs in ..... most situations.
Depending on how well developed your account is, depends on how much you want to worry about secondaries. To a degree......primaries too. However, it's good to get into the habit and better in the long run if you do care about your primaries.
The only real sub-law to this is speed. Although, not quite as important as it was a few years ago, speed is still incredibly important/vital to being better than your opponents. 'If you don't get a turn, how can you win?' Farming mods with speed secondaries is probably more important than farming mods with the correct primaries.
Rule number 1: "The more speed, the more happy happy"