I was in a tier 3 / tier 2 from where moved to Tier 1 thanks to a HR approaching me on linked in. A minimum of one year experience will help. T1 firms always have vacancies (depends on the practice area but gen corp, pe vc, cap marks, banking, etc always will have vacancies at some time or the other throughout the year). You need to make your profile on LinkedIn well and connect with recruiters as they will help you make the jump. Especially November December and March April you will find lot of activity in hiring in my experience. In my view recruiters will be really helpful in shifting from T2 T3 to T1. However, please note that T1s will discount your non T1 experience and might offer you a lower level or might not promote you at the time of joining if you are eligible. This is a standard thing (while it may not be a right thing to do). So if you are an A2 at a T3 you may be taken as an A1 at a T1 and likewise.
Keep trying. The attrition at T1 firms is high and people like us from T3s and T2s will benefit (till we end up quitting the T1s :D). However if you have a decent experience and are good at what you do, the opportunity will come one day or the other for sure.
Listening to folks on LI, I joined a good T3 firm last year. However, tier one firms does not have openings now nor am in getting shortlisted for the interviews. Is the easy transition a lie?
Moving will happen, you need to find the opportunity. Resist efforts to discount experience if possible.
Keep trying. The attrition at T1 firms is high and people like us from T3s and T2s will benefit (till we end up quitting the T1s :D). However if you have a decent experience and are good at what you do, the opportunity will come one day or the other for sure.