Pretty much what LilPhenyl said is what you need to know.
Also be very patient. Early Engineer is boring because of the lack of skills and good turrets. The Toolbox is also pretty useless because the Weak Attack swings so slow that you'll most likely get flinched before it even hits. Use Turrets to your advantage.
Early Meister is boring because the yellow MG is terrible and the only summon you'll have to get you out of trouble is Ash Cannon which is slow (I've actually DIED while the stupid thing was reving up
). You can no longer rely on turrets since they're far to useless as Meister except for Push Turrets/either of the Misc. Turrets.
Also don't bother buying Special Engineer Weapons or the Engineer Cloak (Double Bag) since once you become a Meister you can NEVER use toolboxes again
. They're more for permanent Engineers then Engineers who are going to be Meisters.