PPC and small niches

Some ideas for testing:

1) test different match types - exact, phrase and broad - add negative keywords DAILY on phrase and broad keywords. Put sperate match types in different adgroups so you can be very specific on the conversation rate of each match type.

2) Test different ad text variations - I assume you are doing this already but just to re-enforce - this can make a huge difference on CTR and hence sales / conversion rates.

3) Geographic permutations on keywords if your products have a any type of geographic nature (within your country (state/city etc)) and/or there is some keyword volume for geographic type searches for your products. Test on larger states/cities - again seperate adgroups.

4) Colour or size permutations - as for geographic but using colour or size permutations on keywords.

5) Test different engines - e.g. Google & Bing etc.

6) Do some split testing on landing pages if you are not already - headlines, button text, button colour etc.

7) As you suggest run some international tests - could test this on a shoestring budget by throwing up a sub section of your site on static html and testing CTR on PPC ads.

8) Assume you have mined keywords from your competitors sites etc? For new keyword ideas.

9) Use google keyword tool against your website for new keyword ideas - google will be good enough to suggest keywords for you to spend your cash on. :-)

10) As you have been doing use less generic words but make sure you add negatives daily for non relevant search queries that have sent traffic.

11) If you products are seasonal or gift related try bidding on those 'gifts for xxxx' type keywords - be careful with this - and may have to create seperate landing pages.

hope this helps