Hi Llama.
I haven't had a great deal of success on this game but I'm definitely improving ! So here's my thoughts, for what they're worth.
Give or take a couple of weeks at the beginning and end of the season, the game lasts for about 10 months, which averages out at 3 transfers per month. Initially, I would suggest you use your transfers sparingly (injuries, suspensions, bringing in "hot" players for "not" players).
If you make it to January with 20+ transfers intact, you're in a good position for the run-in. This is when FA Cup involvement and postponed games start to wreak havoc with the fixture list and most of the 2 and 3-for-1's occur. (It's a shame that you can only have one captain per week now

). February to April is usually where I charge up the leaderboard, before realising that I'm too far behind to get anywhere near the top positions. This is usually due to me forgetting to change my captain, or plumping for the defender who is "guaranteed" a clean sheet and probable assists (Mr Baines !!).