Blood Bowl is largely a game of risk management, you need to do all your risk-free actions first, then your most important actions then your most desirable actions. You should always assume a task with any risk involved will fail, so picking up the ball for example, even high agility players with safe hands can mess up horribly, you can however put several players around the ball to greatly increase your odds of somebody being able to pick it up before the turnover when the first attempt fails. Blocks should only be attempted when you can use at least two dice, and you should plan your sequence so that you will on a successful block either push the enemy player into another square where he is being ganged up on or pushing him into another enemy player exposing someone else. Unless your player has the dodge skill or high agility (preferably both) you shouldn't try to run past a block zone unless you need to, likewise with 'go for it' and running beyond a players normal movement zone. Throwing if you have players with throw and catch is 'somewhat' safe at close range but you're always unlikely to be successful if you're sending it long. The best way I found to use the throw skill as wood elves was to combo it with physical hand-offs as you can do one of each per turn and get the ball a long way downfield. Aside from thinking about sequence so that you are more likely to be successful you also need to plan for what will happen if moves are unsuccessful and try to arrange formations so that there aren't going to be gaps and that you can adapt of they do get past the line ect. ect.
There are a couple of good Blood Bowl guides on the steam community that talk about specific teams and the game in general. Some teams are also much easier/harder for beginners than other as well. It's also worth finding the ability tables and the game rules in the manual, because Blood Bowl is a complicated board game and I think this is one game where learning the rules the old fashioned way may be more useful than a tutorial.
Also keep in mind that rookie players in blood bowl are supposed to be useless, it's only when players start to level that they become good, barring the odd exception like wood elf war dancers.