Adwords marketing strategy

What is the best adwords strategy if I want to spend $1500 promoting my app in a month? Should I plan to spend the bulk of the dollars within a few days to get more download velocity? Or should I just spread them out evenly over the month. The aim is to also have the ads increase my rank for some keywords I would be targeting on adwords.

The ads can't increase your app ranking for some keywords, keyword search installs can increase the specific keywords' ranking.
Android or iOS?

Make more Install will increase Ranking , but not increase keyword ranking.

Id suggest FB or iG instead of adwords IMO

It's a travel app targeting India and is available on both iOS and android. Admbob has been giving me cheap installs but those are not keyword installs and not increasing the ranking.

I'm skeptical about buying keyword installs because i've heard reports about developers being banned in the past. What are some other techniques that can be used to increase ranking? I can spend about $1500-$2000/month in marketing.