I'm not going to tell you who to vote for, but here are some tips that'll make it a lot easier.
First, start with one of the shorter ballots: the ELDR council delegation or the International Relations Committee. Read through all the manifestos once, to get an idea of the range of candidates, and what they're saying. Some of the candidates are excellent, others have -well- let's say they've not communicated their qualities quite so well. The point of this stage is just to get a feel for the range of candidates.
Next, you need to break down the daunting task of ranking 20 candidates, by sorting them into a few groups of a few roughly equally qualified candidates.
Think about the experience and qualities required for the panel that you're voting on. Then construct a marking scheme for the candidates. It doesn't have to be rigorous: the point is to sort the candidates into a few categories, with just a few candidates in each. Go through each manifesto, and give it a score out of four or five.
I gave a point for having submitted a manifesto; a point for having clear relevant experience (like having worked abroad for the International Relations panel); a point for sitting members (to promote continuity); a point for mentioning policies that matter to me (for example, for abolishing the Lords in the Interim Peers Panel).
During this process, I found I made a few exceptions. For example, I downgraded a candidate who referred to himself as "one of our sharpest policy brains", and I gave Chris Wiggin my first place vote for the Interim Peers Panel because of his opposition to the Digital Economy Act.
Now, take the highest ranking group, and rank the individuals in the group. Since you've given them the top grade, and there are several places on the committee, it doesn't matter too much what the exact order is. However, you'll find that sorting a handful of candidates is much easier than trying to tackle the whole field at once. The important thing is that you don't miss any out at this point.
Once you've ranked the top group, move to the second group, and so on, until you're finished. Note that you don't have to give scores to everyone, but I found that there were some people who clearly hadn't given any impression that they were qualified (for example, some hadn't submitted a manifesto). Others said things that just irritated me. In order to rank them last, you have to rank the middle range, too!