In google adwords tool for keyword research do i need to look avg search vol or last month search vol?
It's up to you, do what you want Average search volume is better, because of seasonal peaks like christmas etc.
What role seasonal peaks play? Do not u think if i will select high competitor keywords then i can not rank well?
It is better if you choose high competitor keywords, you will definitely work hard to get good rank.. and will surely get good rank
i find the google keyword tool search volumes extremely inaccurate what i have been doing lately is creating adwords campaigns that are "unattractive" and unlikely to get clicked using my keywords and see how many impressions they get, this is way more accurate