Level 7 TH Base
Many of the people have given you their tricks and strategies and it might work too but I am telling you my experience and it may help you alot because in one of my base I am moving from TH7 to TH8 now.
The first 4 things you must do are:
1. Upgrade barrack to bring out dragon.
2. Upgrade spell factory.
3. Upgrade laboratory.
4. build a dark elixir storage.
To make your defence strong for war:
1. Upgrade air defences, as major attacks you will get on TH7 is from dragons only.(in war)
2. Upgrade tesla's and archer towers.
What troops you should upgrade first:
1. upgrade your dragons and electric spell.
2. Upgrade your king.
3. Rest as per your planning but above 2 are must.
While attacking your mirror in war:
1. Destroy one of the air defence with electric spell.
2. Deploy your dragons in enemy base.(strategy and planning is must).
Believe me they will burn whole base.
And don't worry if your enemy 3 star your base in war because there is no base meant for TH7 which can protect it from the attack from dragons. And same goes with your enemy base too. A good strategy will always work.