To positively know in advance? Nah. But there are some things to do to give yourself a pretty good idea.
1. Calibrate recent history. SpyFU, SEMRush, iSpionage and Google & Bing all display data at prices ranging from free to a monthly subscription. All have trials. We like iSpionage and SEM Rush. There are others too. Your mileage may vary.
2. Remember that AdRank in Google AdWords is a simple function and determines ad positioning.. The forumula for AdRank is simply: Quality Score times Bid. Ah, but what goes into quality score? Mostly CTR, but if that is unavailable, Google will project based on the account, the competition and a bunch of variables. A keyword's QS is not turned on by default. You need to change your columns and add it.
3. Make sure you did the needful by syncing your landing page, your ad copy and your keywords. If you're using broad keywords, make sure you have your negative lists in place.
There is a ton more. Head to AdWords and start ensuring you're covering all your bases.
But the most important advice I can give you is this: **You may not need to be in the first three positions. ** You need to run your ads and check your stats. Look at your conversion results after a statistically significant amount of data has accrued. Segment your campaign by position and see if there is any difference between positions. There may or may not be. More importantly, you may be generating a higher return (however you're defining return by not chasing a position).
Do the smart stuff first, launch and calibrate based on real data. Slice every way you can. I have clients who advertise on weekends with a premium and others for whom mid-week rocks.
The first thing to do is to run a profitable campaign. Position preference, a setting now long gone, is best used for campaigns with dozens of conversions across each position while also adjusting for day of week and time of day.
Or you could let Google set your CPC, but I don't think that's appropriate for anyone charging for PPC management services.
Good luck!
George