This works for me.
Save regularly into a Cash ISA - say a £200 per month. Once that has built up into a tidy amount transfer 50 to 75% into a S&S ISA. Continue paying into the Cash ISA and repeat regarding transferring into a Stock & Shares ISA. The repeat is probably 3 or 4 year intervals, doing more regularly than that can be expensive as there is fee for buying the 'Units'. Management costs should not exceed 1%. Invest at risk level 3 or 4 - your IFA will determine that value for you.
You will be making money after 5 years and should be looking at substantial growth (50% poor, 100% good) in 10 years