Mate, I was in your shoes only a few months ago, and after talking to some very experienced people this is what I came up with.
1. Get ALL your CPL and IREX subjects out of the way BEFORE you start any flying. Too many people have flown part-time (due to work or finances), go right to the flight test stage but couldn't go on because they hadn't finished their subjects, or they tried to work full time, study and fly... at least one usually suffers with that strategy.
2. After your PPL and subjects, do you night rating, the hours count towards your CPL and gives you your 10+5 required for the CIR.
3. Build some hours, you need the command time for both, and it's a good consolidation exercise. Be hard on yourself. Don't use a GPS, do your GS checks, CLEAROFF's, Revised ETA's (and get them within 2 mins everytime), keep your altitude +/- 25 feet (CPL and CIR don't give you the tollerances allowed in PPL), get your radio calls down pat - read: should almost be verbatim out of the AIP (again less tollerences with bad phrasology than PPL), fly your plans accurately, work out your drift and 1/60's and most of all, don't accept 2nd best out of yourself and your flying.
4. Once you have managed those things, then think about whether you want to just finish the reletively few hours left for your CPL or get a CIR.
I have talked to many guys and girls, some who did it straight after getting their CPL, other who have waited a while. All agree that the skill level and experience you *think* you have after CPL(let alone PPL) is nothing compared to flying in the real world and that they all realised they knew jack.
Most people who come back to do their CIR will get it close to minimums, whereas fresh CPL'ers can be hit and miss as to whether they will get it in the minimum time.
Just my 2 cents.