influencing other states

The biggest thing you missed is that basically you shouldn't try to go head to head with France.

France has LOTS of influence to throw around, if you want to take countries from France's sphere you'll have to do it 1 at a time, and you'll have to be clever about it.

When your influence is building up, keep an eye on France. If they discredit you, keep at it and ignore it. If their influence is getting close to 50 though, just stop, stop influencing them altogether and wait until someone else tries. France will then use their influence to knock that other country down and you can resume the process until France gets close to having 50 again.

Eventually you'll get there, but influence battles with France require some serious micro-management, likewise with Great Britain.

Not true, often Austria will give it a crack on its days off, and America strangely shows an interest once it's got it's local area under the thumb.

The other handy thing is that Two Sicilies has a reasonable chance of becoming a GP, which always serves to disrupt France's Italian collection.

If only one other GP is interested in sphering your target, and they are seriously interested, then its going to cost you a large amount of influence. If they are much bigger than you, or the continent/neighbour bonuses are against you, you are going to find it difficult to impossible.

However, once muliple GPs are interested you can always play them off against one another. The AI will never use its influence on a GP unless that GP is actively influencing at the time. Just set your priority to zero when the AI gets close to 50, wait for it to use its influence on another AI, and then set your priority going again. Keep a portfolio of targets and move your influence to whatever one the AIs are low on, and as they get towards 50, shift somewhere else.

You can also play games with the level you set your priority at. If you have just one target, all your influence goes to it whether you set the priority at 1,2 or 3. However, the AI will respond differently. Similarly, if you have attracted a ban or have accumulated 100, it doesn't matter what priority you set, you don't add any influence, but it does affect what the AI does.

Once you realise the AI only acts on the basis of the priority you set, rather than the position you are in, you can run rings round it in the influence game.