The length makes no difference. However, the keywords themselves need to be things that are being searched for regularly AND that you actually stand a chance of being found for (ie you're on or pretty near to page 1).

Google Keyword Planner is a cool (and free) way to find out how many people are searching for your keywords every month. To check out the competition, just search for various combinations of keywords in google and see what sort of sites you're up against. There's more to it than that but broadly iif you see page 1 locked out with really massive sites then that's going to be an expensive keyword to target.

In theory if you stuff in more keywords then you stand more chance of hitting on something google likes. But if it looks unnatural to users then you'll have a disadvantage from that point of view.

Best approach in my experience is to research keywords thoroughly to find any big opportunities (ie high search volume/low competition). Target those opportunities in particular but otherwise just build content that looks naturally good to your users. A very large proportion of google searches are unique so you can rely on the fact that good content and good backlinks will get you hits!

Hi,

First a disclaimer - I have a lot of experience designing/developing large web apps - less with mobile apps but similar principals apply for sure.

The service you need first is someone to help you to define the functions your app is going to perform. So I'm not talking detailed screens and I'm not talking detailed tech questions. But I am suggesting you work with someone to get very clear on how the functionality of your app relates to your business plan. ie what features are most important on launch, which ones you are planning to develop soon after.

This is a consultant you're looking for although plenty of developers/designers will be able to do this job quite effectively if they also have business experience.

Once this information is clear then you would probably want to contact a developer for rough estimates on development costs/timeframes for each module you are building. They'll make decisions about which pre-built components to use in your project. Then you can weigh the estimates for each function against their projected financial value.

With this information you can get the UX guy to create detailed schemas for how the first release of the app will look from the outside. And you won't be wasting any time/money because the broad areas you're working on are already costed approximately with the developer. Then you can take the UX guy's output and send it to the developer to get much more precise estimates and you can make your final choices before pressing 'go'...

You will probably find that from a development perspective there will also be 'known unknowns' - no matter how skilled/experienced the developer they will not necessarily know off hand how long tasks will take. So often you'll need to pay them to explore these areas to get a proper costing. It depends how big/complicated your app is. Sometimes the developer will be keen to learn or to impress you and get your business so some of this they will absorb themselves.

Lastly, when the UX guy has done his job, make sure you get from your developer a proper costing for each module of the app. So we're talking something like:
First Screen - 300usd
API connection for 3rd party integration - 800usd
Video display page - 800usd
...and maybe even a break-down within each section.

Then make sure to get your developer to define a timeline with verifiable milestones for payment. So there may need to be advance deposits at some points depending on how your developer's business is structured but make sure that there are points where you can say 'when I can do X and Y and see for myself that it works' then 'payment is released'.

Sometimes the budget and the timeframe/milestones data will need to be revised but at least this can be a collaborative process between client and contractor. The better you communicate the more successful your working relationship will be.

With the best will in the world there are still often budget overruns but you can minimize these with the practical systems I've defined above and also by being as unambitious as possible with the technology within the bounds of what your business demands. So you can be as ambitious as you like with the business but always build the minimum sized tech solution you can because I guarantee you, the day your project hits the public, your plans will change and you'll be glad you've got time and money left over to respond appropriately:-)

I hope that helps, if you have further questions I'd be happy to help.

Best,
Rob