Loc-tite is a liquid brush-on. There are different types (colors). Get the version that is not a permanent attachment (I believe it is blue). You want to put loc-tite on all the screws that you worry about vibrating loose. Like the screws that hold the motor mount to the firewall. Don't use it on the servo screws though. If your landing gear use machine screws, put it on them also.

For attaching the servo, you want to predrill the holes. I use a pin vise that I picked up at the hobby shop. A pin vise is just a handheld drill for really small drill bits. The drill bit clamps in the end, then you drill it by hand. The hole does not need to be that big. I usually use the smallest drill bit that came with the pin vise. The predrilling just helps the servo screws to start in the wood without "walking".