This is something I'm doing myself. Each year I do a career mode, usually with Man Utd. This year I wanted a challenge, so, I put up a poll on here and people voted that I manage Nott'm Forest. Believe me, just using a Championship team is a challenge enough! Plus I used the financial difficulty set at strict which, I regret doing now!
Anyways, so, go over to sofifa or check out Fifascoutingtips on youtube, that way you'll find the best, cheapest players.
I would say have a plan. I created a four year plan of gain promotion to the Premier League, not get relegated and finish mid-table, win the Premier League and finally win in Europe. All the while, building for the future, so I can leave the club rich and with lots of potential going forwards.
So yeah, look at good scouts, I wouldn't go anything below a 3 star judgement, 3 star experience scout. They can occasionally bring back good players.
Also after a few seasons, when you start to have some money, look at not buying players but sending your global transfer network scouts out to search for players on a 0-1 year contract. That means come January you'll be able to basically get free players and only have to pay for their wage. I just got Per Mertersacker from Arsenal on a free transfer.
You need to find that balance of developing youth and having experience within a team.
Try and win the capital one cup or basically, just exceed board expectations and they should reward you better.
Last but not least. BUY SMART! Don't go out and spend all of your financial takeover money on Messi. Sure, he's a great player, but, look to the future, think of getting the most for your money. You could buy 5 or 6 players for that amount of money. Players than will develop.
Personal recommendations would be Britt Assombalonga and Luciano Vietto to good strikers with a lot of potential!