Writing a guide is harder than I thought.
My in game name is NotApplicable. Funnily enough, I reached #3 spot on ranked with Blue Beetle.
Anyways, some pointers to go along with whatever Dawnbase allowed me to choose using their interface. This is how I play Blue Beetle in the jungle.
Skill Orders
Q first. Why? Damage. The burst on Q is what makes Blue Beetle very strong in my opinion, so max it out. To be successful with Blue Beetle, you must be able to land Q on your primary target consistently since the AoE damage isn't as good as the first hit damage. The range is respectable and at early levels, hits very hard. In fights, you should always aim for their squishiest member without placing yourself in harms way with this skill.
Passive is the next skill to be maxed. The reason is that the other 2 skills are utility skills and we want damage first. Leveling the passive brings the cool down to a much more useful 6 seconds from 12 seconds and increases the damage by a lot since it is true damage. It has respectable scaling as well.
I max E after since again, I want more damage. E does a lot of damage, but you should save it for escapes. Many a times, I baited people only to kill them with a Q - E combo due to its damage.
I max W last since it provides no damage and only reduces cool down on rank up. The skill is not to be underestimated however, since you can use it to scout and as a free ward for a time being. At rank 1 , the cool down is 20 seconds and that is more than enough since you shouldn't be needing to spam this. Decide when to fight by using this skill to scout. Don't be diving into a group.
Max your ult whenever possible like most champions. One thing to note is that your ult skills depend on your ult level, not your individual skill levels.
Item Choices
My starting items are marauder knife 2 and health vial 2. Basics starting in the jungle. Some might opt for marauder knife 1 and coda 1 and that is fine as well. The problem with early coda is that jungling will be slowed since the % dmg is rather huge with Q when clearing the camps.
My core items involve leveling marauder knife up to tier 3. At tier 3, you gain will sustain thanks to syphon and the 30 damage lost on hit will be more than made up from the increased % damage on Q. Since Blue Beetle lacks CC for those early ganks like certain champions, I use my superior jungle clearing speed to invade and harass the enemy jungler. Coda 3 is a must for AD champions at this point in the game. Deathstroke's claymore helps with further armor penetration.
Now, the offensive and defensive items are dependent on team comp. If the team is tanky enough, I will usually build the crit and become a secondary marksman. If another bruiser is needed, Ra's robe and Lobo's is a good way to become a nuisance.
The situational items are there because they are situational. After the coda and claymore are finished, you have lots of freedom on how to buid. The timepack has a great ability which allows you to jump in and get back out rather easily. The visor gives much needed attack speed and boosts your will reserves. Both items are decent on blue beetle and I will build them if I am ahead and the team doesn't need another marksmen or bruiser.
Stolen Powers
The detonate is self explanatory for a jungler. It is necessary for control of the elites and raiders. Not necessary for doomsday device since your entire team should be there unless you are going for early doomsday. Blue Beetle can solo doomsday at level 10.
The super strength brings you on par with most assassin junglers during early game. The super strength provides the much needed CC and allows you to line up your Q and E for maximum damage. Furthermore, since Blue Beetle is a ranged champion early on, you should be able to 100 - 0 most squishy champions even in top lane through Q - E and auto attacks with super strength.
Mods & Augments
I normally opt for all +10 damage mods to boost Blue Beetle's early game so that jungle invades and ganks will all work in your favor. It doesn't hurt to switch mods around but it might hurt the early game damage.
Augments all improve penetration to help with Q damage early on.
Still a Work In Progress. Leave a comment and maybe I will update.
where the FUCK is the 'guide'? 