need some gameplay advice

No matter how I play I can't seem to avoid getting attacked by every country whos close enough to me. I don't really know what could be causing this, at first I thought it might be because I get excommunicated a lot because the stupid pope wants me to cease hostilities when I just defeated the enemies armies and soon i'll capture a city that I am beseiging. So In my next games I tried my best to do as the pope says, except for going on a crusade to jerusalem, because playing as england it would just take years of gameplay time to saild around spain and through the meditteranean with no friendly ports in between and with the risk of getting attacked by the egyptian fleet which seems massive.

Anyway the only other thing I can think of is that I hate diplomats, merchants, princesses , assasins, spies and armies entering my territory... not only is this just downright annoying, especially when they walk into my merchants and bump them away causing them to stop producing gold, but the amount of time it takes to watch the computer movenments is just incredible because of there stupid pointless wandering around with diplomats (they arent even going anywhere just stroll back and forth) so I kill everything that enters my territory (but dont get caught) at least i dont think i do, because war isnt declared war at that point, but later when an army just walks to my city and starts attacking it for no reason. BTW why are the computers merchants so highly skilled and competing mine away when we only just started playing? with 7 out of 10 skill level

In my most recent game I even avoided killing anything except enemy units that come to my territory, and i made an alliance with milan, who then approached paris (which was in my hands) and rheims and started beseiging both of them, they was my allies for fk sake, i did nothing wrong with them, i made a trade agreement, i dont walk around in their territory (i have got messages that the computer doesnt like it when u do that to them)
So why is this? I just want to play a game where i can defeat my enemy and everyone else and their dog doesnt gang up on me.

BTW2 why does the pope never go along with a crusade i want? whatever my standing is?

So, in my experience, the single biggest factor in the M2TW AI besieging your settlements is the size of your garrison.

You can cut down a lot on the enemy attacking you by garrisonning all of your border cities with at least a half stack or more.

Still though, eventually you'll be at war with your neighbors, so plan accordingly -- It is after all a time of total war. Make alliances early in the game with nations that are far away. And don't expand in a way that will cause you to have too many areas to defend at the same time.

WRT the pope it seems that having a higher rep makes a difference in the pope accepting a crusade target. An easy/cheap way to get your rep up with the pope is to frequenly have your diplos offer the papal states map information.

Getting a pope from your faction will also help you picking out your crusade targets (I think.) To get your own pope concentrate on getting lots of priests promoted to cardinal -- train them in cities with cathedrals (and ideally theologians guilds), and send them out in groups of 3 to orthodox and islamic regions.

If you are playing on Very Hard "game difficulty" then AI will attack you even if they have 3 other countries at war with them. In VH everyone turns into bloodthirsty kamikaze with one purpose in mind: annihilate the player-controlled faction.

can anyone verify if its true what i heard today.. the using princesses to make royal marridges drastically increases reputation with said c ountry?

yes a marriage alliance will usually last much longer and is more reliable than a simple alliance...

Furthermore, IIRC, Marriage alliances have relations remain to the good for more easily than with a simple alliance...

usually, a marriage alliance is useful to keep one front secure while fighting on another...

Say, you are the French, if you want to get rid of the English you should sek a marriage alliance with either the HRE or Milan as they are most likely to attack you...

i have never seen the ai break a marriage alliance with me by attacking something like a port.marriage alliances will last much longer then if you just had a alliance with them.

Unless you've grown big (the AI gangs up on the top three) the AI largely bases its decision on the total military strength in the border provinces. This actually means that it is a disadvantage to have a short border in terms of number of provinces, since you logically build up a "border garrison" to a size proportional to the number of border provinces. What the AI doesnt do is look at the garrison inside cities, or whether forces can reach the hot spots within a turn or not. It only looks at the strength in the entire province (I suspect this is an AI remnant from the earlier Total War games that had a risk style map).

So what can be done about it?

1) Avoid having a lonely province surrounded by the territories of one adversary (Venice, Sofia, Antwerp, Caen, etc) unless you have the money to pay for upkeep of a few extra stacks sitting in forts, which gets expensive fast.

2) Let the AI hold lonely provinces surrounded by yours. As France I take Brussels and Rennes, and the English have NEVER started a war since they compare their Caen force strength to that of my four border provinces and find themselves outnumbered even if I only keep militia stacks in the cities. I also let the Danes take Antwerp, and if I garrison Brussels properly they wont attack me due to being outnumbered.

3) Avoid certain islands unless you control all nearby mainland provinces. Corsica and Sardinia (Ajaccio-Cagliari) will be the targets of all manners of weird attacks, as the AI makes even less rational decisions when attacking islands.

4) If you have a 1:1 province ratio along the border with an AI faction, build one fort per province and put in extra stacks there. I manage to keep the notorious Milanese perfectly peaceful if I have full garrisons in Marseille and Dijon and have one fort per province (preferrably in a strategic mountain pass and within walking distance from the city).

5) As a catholic: focus on excommunicated factions (call crusades against them if feasible) when fighting catholics, and bring siege machinery when attacking non-excommunicated ones. Make an alliance with the pope in the very beginning (and dont go rampant on sacking prior to that, as that will make the alliance harder to come by).

6) Release prisoners after battle. This helps your reputation and makes it a bit easier to make deals with the AI. I find that if I keep doing this I can afford to sack cities and still keep a reliable reputation:p

7) The AI is very unlikely to make peace with you until you either outnumber him in the border provinces or dont have any common border at all.

Basically it is defensively sound to make the AI have a short border with you rather than the other way around, which is the total opposite of strategic good sense:p

Also a nice idea is to just give the AI some gold. Now it might seem like a waste, and at the start of your campaign it's a bit hard to do (since you'll be strapped for money), but 5000 or so (which is less then the top buildings you can build at the end) will come a long way. Or make a tribute for 1000-2000 per turn for a while.
If you can spare it, that will get relations up in no-time, while also making sure that whomever you helped gets a good push. It's a good way to sandwich an enemy country. send a diplomat to a country right behind your enemy and try to get an alliance this way, and if you do it right, you'll soon be having borders with your new best friend.