The fundamental thing you need is a team. Before we get into more extravagant challenges, custom teams and all that hoo-ha, we need a base club to get intimate with the game.
When I first played 01/02, I made the shameful mistake of playing with a crippled Nottingham Forest team, who had finances that looked like some of Neymar's hairstyles. Within a month, the club went bankrupt and I got sacked 6 months later. I was, however, somewhat proud of how long I lasted. This is what not to do at the very start.
If you want to dominate not only England but the entire game, play with Manchester United. Of all the classic games you can play, United are the team to beat for the most part. This team is peppered with talent, which is fairly realistic given how good they were in reality. If you build the team around the real-life flop Juan Veron as an attacking midfielder on his own, this team will struggle to lose. You don't even need to sign anyone, they just have the best team. Their backups could outclass some Premier League outfits alone. You just can't make a mistake with United. Arsenal, Liverpool and Leeds (yes, Leeds) are all decent outfits to start your career, but as mentioned before, good luck beating Fergie.
If you don't like England, Italy is a highly competitive league and is where I usually manage. The team to beat here is Roma. As unbelievable as it sounds, they are the hardest team to beat in Italy. However, it can be done with the likes of Inter, Milan, Parma, Lazio and the scum (Juventus). This is based on winning the title; any team can upset Roma in a league fixture (same with United.) I believe Walter Samuel is the most valuable player at Roma, however, Antonio Cassano is the guy that tears teams apart; he always does it to me.
That said, Inter Milan can also control Italy, although it's pivotal that you sell Ronaldo. He's just rubbish. Always injured and when he isn't, he won't score. You're better off with Recoba or Ventola here. Other than that, they house a solid defence, a cusp elite tier keeper, and a midfield that needs a little work but Vieri always finds a way to carry Inter.
Milan on the other hand often uses their world-class midfielders to try and dominate games, though their defence leaves a lot to be desired (as weird as that sounds). Although I support Inter, my favourite team to play as is Parma, with the best keeper in the game (arguably) Sebastian Frey. Overall, Italy is the most enjoyable league to play in - in my opinion.
The French league is a bit mediocre. You've got PSG and Monaco, with Paris boasting Ronaldinho. The Dutchies have Ajax (Van der Vaart), PSV (Arjen Robben, Van Bommel) and from memory, Feyenoord (van Hooijdonk) can scratch some heads. Germany has Bayern (Kahn, Elber, Pizarro), Dortmund, who won the league that season (Worms, Koller). Leverkusen can also cause some havoc with Berbatov and Ballack (Lucio is also a huge player in this team).
I won't bore you with the rest of the leagues that are available on the game, as I'm sure you'll be able to find the team that you find enjoyable to manage.
If you feel especially confident, there are various challenges that I (or some friends) have played and either have conquered or failed. These include;
• The classic "Road to Glory". Most enjoyable with 3 or 4 leagues selected at a minimum, and have your manager's nationality the same as one of those leagues. Find a club that starts without a manager, and take over them. As weird as it sounds, resign from the club immediately. Go to <Manager Name> -> <Go on Holiday>. Make sure "Apply for jobs with a higher reputation" Is selected, and wait anywhere between 3-6 in-game months. In FM terms, this means hours of waiting but don't panic; this usually takes about 5-10 minutes. I usually set the goal of becoming the best manager in the world as per "Manager Stats", but it's up to you. Feel free to get sacked and move on as much as you like. My current rendition of this game has won me a Premier League with a West Ham outfit. The current year is 2038. If you are impatient, this isn't for you. But trust me, it's addictive.
• The other classic; Saving <insert team>. Pick a team struggling in a specific division (for example Nottingham Forest) and trying to win the top honour in that country. Easy in concept, difficult in practice.
• An idea by www.cm9798.wordpress.com (David Black, the Lord of 97/98) that he calls the CM97/98 Retirement Home. This one is a bit harder, as it requires you to either; clear out the squad of a random lower league team and inject some funds, or create a custom team (this can be done in the Editor). The aim is to sign players that are only aged 35 or older and try and win the division you've been entered into. The website has all sorts of outlandish concepts; I highly recommend having a look.
• Come up with your own! Anything you challenge yourself within FM is most likely possible with CM.
Similar to FM, it's important to design the right training regime to get the most out of player development. Check to make sure you have adequate staff, and organise a few friendlies. I often like to play a home game against a large team in the same continent but not the same country. For example, if I was Nottingham Forest, I could play a friendly against a team like Club Brugge. Two away friendlies should follow, and these should be against other English teams. These two away friendlies should go before the home friendly so the team can get used to your management against lower-level opposition. That's not how you have to do it, I just prefer it that way.
Finally, if you wish to manage a national team, it's easily achieved. Once you've started the game, choose a low league club and retire. Add a new manager and use the Nations tab to select your continent and eventually nation.
Now that you've chosen your team, it's time to set things up. You want to initially get to know your team (as any FM player would do), as well as recognise the strengths and weaknesses in your team. This brings us to the next part of the series, and it's my favourite, signings!