options:
Off the shelf
Franchise
Startup
Google all the above for pros & cons.
Choose an industry you know about.
Plan Plan Plan!
Budget everything and then load your final figure by 20%
I've done a few startups now which I have sold on for profit and its pretty hard but very rewarding as well.
If you are buying off the shelf cut out the agent in my experience, deal with the business owner direct - it cuts out the bullshit and price hikes.
Also remember if the business is for sale there may be underlying reasons for this, check their books and make sure they are verified via accounts/tax records.
Ideally get a silent partner involved.
Think about buying a failing business - you can get these on the cheap and make them profitable in stages. Look at what you could add in terms of value and content
Alternativley look at doing property, good returns and its a buyers market at the moment. Dont be too scared of whats in the media, still lots of good deals out there. Ive just bought two properties in the last two months both of which are making me £450 a month just on 'rental VS mortgage payment' - if you are in it for the long term a short term downwards trend in the housing market is negligable as it will soon start peaking again (unless theres a crash which is not immennant) PLUS if house prices are falling less people buy and more rent - this means a bigger letting market. after 6 months + you can remortgage the equity and buy another two, before you know it you will have a portfolio earning you a nice little packet. You can easily borrow initial funds for the deposits especially if you are a home owner, just dont tell your mortgage company what you are borrowing for
Hope that helps