I'm going to give a summary of the basic strategies and what's important at the various stages of BP/WWBP.
This is primarily devoted to Anon WWBP, as the effect of diplomacy on the game is beyond the scope of this post.
There have been cheating long ago in Anon WWBP, but I've done very well without cheating, I think blatant cheating isn't done in these games.
Also, BP is usually won before some or most of these stages.
First stage: grabbing minors. Money is of primary importance. Attacking one neighboring minor (recommended) is usually possible without much loss, although it might be wise to move F to the ocean and take some losses. Advantage of F in the ocean is that it fights both in the sea and in the air and can't be suppressed by missiles, also small advantage in that HPIs aren't lowered for losses when it fights based on land. Attacking two neighboring minors can be done to increase money further, but F can't be moved to sea and there will be significant losses. In first two turns, spies should be preserved for later, but money can potentially be used for Cspies and token research, particularly a little on spies, Cspies, I and F. Occupying minors costs in the short term military power, but as a trade-off, can gain money to spend on other minors.
I usually spend $99 on minors the first turn and $1 on I research. Second turn and third turn, anywhere from
50%-99% on minors.
Note: research usually returns square root of amount spent for industry, espionage, A/N. 50% of square root for M,X.
F was cut to .75 of square root to hinder players like me who like to build a lot of F.
Second stage: War. If needed to crush opponent in his primary sea space, may want navy, but I don't recommend N research -- F is much more important, and in the long run, F multiplier will be higher than N multiplier, and F will be built rather than N, thus making N research a short-term prospect only (at least the way I play). A is often necessary in early war too, but I definitely don't recommend spending more than $1/turn at most on A research. F has the advantage in that defending, it only loses at most about 1/4 (unless you have allied your attacker) of it's amount, while A loses the whole thing. Also, F has a bigger range and unlike army, can fight at sea in sea battles. Strategies in early war are beyond the scope of this post, but being bigger helps a lot, and having spent money wisely on minors is likely to make you bigger. I research is very important while fighting, looking to the next stage, while for me F research for the next stages of the game is also very important. I traditionally haven't emphasized spies and Cspies, although I've often wished for more spies, and have been hampered in my attack by opponent's Cspies.
Third stage: Further war/ industry build-up
At some point you want to stop building war materials and start building industry. If you're lucky, you can keep expanding by fighting, if not, close down the war and hope to build up industry. Industry multiplier is still good to have higher, 100 or more, but F multiplier (at least for me) and the spy and Cspies multipliers are much more important at this stage (and due to the research result formula, possibly even earlier.) It's also never to early to start working on your M and X multipliers, in case the game goes to fifth stage.
Fourth stage: Pump out war materials with your greater industrial base.
All my games have been won in this stage, sometimes fighting several opponents at once, by working on my I and F multipliers early in the game, building industry among the earliest of the players, and pumping out massive amounts of F and significant X and M.
Fifth stage: M used to wipe-out industrial base, X used to defend.
There have been other posts on the strategies of M, but in this stage the M/X multipliers are the main contributing factors. Wiping out a region of countries' industry with M can lead to the suppression of industry with only 1-2 M/country. Such success can easily lead to a smaller position beating a bigger position.