You seem to have already found that being chief,and play your own game is not an easy task, and that this situation may continue. 

A lot will depend on your skills, and the other people in your clan.

If your previous chief is still playing you could ask for information and advice,if not, hopefully others will help you with your specific needs regarding the stronghold during competitions.

Though I suspect that you will run into the same kind of problems you found by trying to get this information by joining the other clan.

You may just be luckier getting the information secretly, as anything here is for open consumption.

I'm in a similar situation but have been running the clan for about 4 months now and playing for about 6 months.

Main thing is to keep communicating as much as possible - e.g. send out messages a few hours before clans battle to get people to pull their rss tile farming in time, check their shields etc.

Promote those that are active and give them a role to help you run the clan - e.g. search for new recruits up to your max clan members limit, look after SH material conversions (try and time each rss transformation at around 7 day mark so you don't use too many resources each time, but the end time occurs near the end of your weekly clans battle event).

Make sure you have a clan bank who will never let their shield drop.  Each day you will pay a levy to whoever controls the place of power.  This is 10% of the chiefs total silver so if you win a CvC battle, you could get over a billion silver as a reward.  You don't want to waste that so transfer it to a clan banker (I created a mini account to do this myself).  

Your SH can research some great equipment to help you all grow faster.  Check with the clan to see what special equipment pieces they need most.  Personally, we started with equipment to boost building - e.g. Haakon's boots, Bjorn's Helmet.  

Your SH also undertakes its own research in shaman's residence.  Try and have something being researched at all times.

For other tactics, read through these forums and also some of the external wiki sites for general strategy tips.  It depends on the type of clan you want... PvP snipers?  relaxed farming clan? world domination?  Also start chatting with one of your kingdom clan leaders and see if they are happy to share any tips.  

Good luck 

The general rules for competitions are, that you have to be in the clan before the event is announced to score in them.

There are some other rules about leaving and rejoining and leaving the clan before the competition ends and transferring the chiefdom.

I do not know them off by heart , but they are scattered throughout the game and the forum.

Maybe someone will collate them.