You should have settled into a routine of work by now. Your transfer viva from MPhil to PhD should have been undertaken if you are full time - if part-time, then this will work pro rata time-wise.

As well as doing the actual work of the PhD, you should be developing your personal skills and competencies - so looking for opportunities to write papers, do presentations and teaching and generally develop your academic competencies.

Start to think about writing up - if you do that now, you might realise that certain "killer" experiments are required sooner rather than later - the good news is you have time to do them (rather than leaving them to next year when you are struggling to find time to write up). At least create a thesis plan and discuss with your supervisor. 

Make sure you keep in regular contact with you collaborators and mentor; they like to know how you are getting on and often have good nuggets of insight and advice.