Three factors affect speed of specific training:
1) age like hattrick (because players need to be more welll rounded in this game I do take trainees as old as 22, if they have good secondary skills. They'll be the first one I sell though.
2) Talent- Hidden attribute of the player (use one of the sokker tools (ie sokker manager) to track this)
3) Skill level - low skills rise faster
ex: a young highly talented player will rise from average to adequate in two weeks, from good to solid in 3 weeks...
General training: all players who played in a game receive it. Trains slower than specific but allows for improvements in skills that are not being trained specifically.
Main coach: needs to be "unearthly" in the skill being trained. High rating in relevant secondary skills do help, but too expensive for new teams. As you win games, fill and upgrade your stadium and promote, you'll be able to afford better coaches.
Assistant Coaches: They help with both specific and general training, only general appraisal matters for them. Three of them is the maximum, stay with three if you can, cut down to two of them if you have too.
Very important only general appraisal matters:
1) Start with an excellent/formidable youth coach
2) Only keep youths that will reach "solid/very good" skill coming out of the school based on about 5 weeks per pop. Use Plus one of the sokker tools (ie Sokker Manager from Guacamole's home page) and it will be easy to track talent for both youth and players.
3) Timing is important, when you have a few players coming out at about excellent/formidable upgrade to an outstanding/incredible youth coach. You can have your youth graduates pay for your better Youth coach and you can even keep the talented ones.
Coaches are very important in Sokker. Training is the best way to improve your team, plus making money on sales of players who aren't in your main squad to upgrade elsewhere. At first you wont' be able to afford an expensive head coach, and that's fine. Just get a head coach that's unearthly in the skill you're training, he's good enough at first. Whenever you can you want to upgrade though, as multiple high skills help for general pops (you train much more on the skill you're focused on, but mebbe 10% efficiency on other skills that are unearthly, and lower at lower head coach skills). Some new managers also have 2 coaches with different high skills (magical or unearthly) and swap them out based on what they're training that week, using the other as an assistant that week. That's a good strategy as well.
I had an operating deficit for most of the first 2-3 seasons - you MORE than make it up in sales of trained players. By Far. You should be losing 10k or so every other week (ie mebbe even the week of home match and losing 10k the other week). A bit more or less is fine, depending on how aggressive you are. Just don't go much lower than -150k or you'll start to worry about bankruptcy.
When you search for an assistant or junior, look at the transfer list for coaches and see what wage you can afford (look at the solid coaches, see what the lowest wages are, then look at excellent, etc). Then i'd suggest you try to pull the coach, tho you can get unlucky and have this be expensive. However, at the levels you're looking for the pulls will be relatively cheap.
Coaches wages are drastically affected by high skills. So an excellent coach with a few unearthly's and a few tragics which average out to excellent will be MUCH MUCH more expensive than one with all excellents. Also, keeper skill is more expensive than the other skills. Therefore, a coach with everything about the same except keeper which is 3-4 levels lower than the others would be the optimum wage. And would help exactly as much as an assistant than one that's more expensive with the same general appraisal (ONLY the general appraisal counts for assistants and main).
So what you do to search for an assistant or junior coach is set everything to the same level (say excellent) except keeper, which you'd set to 3-4 levels lower (adequate or good).
Make the pull, if the wage is good, keep, otherwise reject and move on. Don't leave unwanted coaches in your squad unassigned, you'll still pay them. But you can keep them there unassigned while you're seeing if you get a better pull and then keep them if you give up or reject them if you get one better.
To pull a head coach with one unearthly skill who'd be the cheapest possible, set that one skill to magical and then EVERYTHING ELSE TO TRAGIC. Don't leave everything else at any, as you'll get random skills in those other stats and it'll be expensive.