This is so very vague.
When we go to London we stay in a Premier Inn, clean, basic, you know what you are getting and a good hearty breakfast. Rooms are relatively cheap and that's fine as we just want a base and don't spend substantial time in the hotel, you can often get interconnecting rooms if travelling as a group which is useful. We normally go for the Richmond or Stratford one as being slightly further out the rooms are bigger.
Richmond is great for Kew Gardens and Hampton Court and feels very safe to walk around
Stratford is great for shopping and transport links.
If it was my first time in London I would want to do very London specific things so something like:
Day 1) Kensington
The Natural History Museum, Science Museum, V&A, Royal Albert Hall are all close together so something there for part of a day just get timed entry tickets to avoid queues.
Day 2) Centre
Walk through Westminster past the houses of parliament, Downing Street, to Buckingham Palace. Or walk from Westminster to London Eye (I think this is overrated) and Southbank for The Globe and Tate Modern or walk into the centre for National Gallery and Portrait Gallery and go to Trafalgar / Leicester Square and covent garden
Day 3) Tower of London
Ger out at Monument where fire of London started and go up the Monument for the views this is cheap, views are great but it is a spiral stair case. Then walk to the Tower of London
If you have a longer trip
Day 4) Kew gardens
Day 5) Hampton Court
I'm not a foodie so happy to go cheap or street food but I love theatre so I'd head back to my hotel to freshen up and then fit in a show most nights if I can.